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Abbreviations, Definitions and Opinions

Courtesy of Morris L. Hallowell IV

Index:   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   V   W



1. Acanthus Scroll - An engraving design patterned after any of a variety of plants of the genus Acanthus, native to the Mediterranean, with large, segmented, thistle-like leaves.  Photo

2. ACP - Automatic Colt Pistol.  A proprietary designation for a type of rimless cartridge design, such as .45 ACP.

3. Action - The receiver of a gun containing the firing mechanism.   The serially-numbered, legal soul of a firearm.  Major types are: Boxlock, Sidelock, Blitz, and Bolt.

4. AE or Automatic Ejectors - fittings inset into the breech end of barrels of a break-open gun that kick out fired shells, while only raising unfired shells enough to be removed by hand.  Photo

5. ANIB - As new in original box.  Perhaps fired, but in virtually new condition.

6. Anson Forend Release - A latch for securing the forend to the barrels of a break-open gun, operated, via a longitudinal rod, by a pushbutton exposed at the very tip of the forend.  Typically seen on Purdey and Boss guns.  Photo

7. Antique Firearm - Defined according to Section 921 (a) (16), Title 18, U.S.C. as:
A.  any firearm (including any firearm with matchlock, flintlock, percussion cap, or similar type of ignition system) manufactured in or before 1898; and
B.  any replica of any firearm described in subparagraph (A) if such replica (i) is not designed or redesigned for using rimfire or conventional centerfire fixed ammunition, or (ii) uses rimfire or conventional centerfire fixed ammunition which is no longer manufactured in the United States and which is not readily available in the ordinary channels of commercial trade.

8. Articulated Front Trigger - A hinged front trigger, built to cushion its impact on one's trigger finger as the gun recoils when the rear trigger is pulled.

9. Automatic Safety - A safety catch on a break-open gun that resets to the "safe" position each time the gun is opened, via a limb attached to the toplever spindle.

10. %blue - Bluing is a thin surface coloring, induced either by heat or by polishing and the repeated application of an acid solution to form a type of blue-black rust.  Bluing reduces the reflectivity of polished steel parts and helps inhibit further rust.  The percentage of original blue finish remaining is a quick indicator of the condition of a gun.  In our condition descriptions, 98% blue means raw steel is showing through 2% of the overall blued surface.  We try to describe the percentage of finish neither optimistically nor conservatively but exactly as it is.

11. Back Action - A sidelock action where the mainspring is mounted rearward towards the butt.  The back action is often used in double rifles where the need for strength requires as little steel as possible be removed from the bar of the action.  Photo

12. Backboring - Enlarging the internal diameter of a shotgun barrel beyond its proper standard (.729" in 12 gauge) by reaming, in an effort to reduce the recoil.

13. Bar - The portion of a break-open gun's action extending forward from the bottom of the standing breech, supporting the hingepin.  In modern side-by-side guns, it is usually machined to accept the cocking limbs and the main locking bolts as well.

14. Bar Action - A sidelock action where the mainspring is mounted forward into the bar of the action.  Often more graceful in appearance than the back action.  Photo

15. Barrel Length - The length of a barrel as measured from the muzzle to the standing breech in a break-open gun or to the bolt face in a bolt-action rifle, including the chamber.  A revolver barrel measurement does not include the cylinder, only the barrel itself.

16. Barrel Wall Thickness - The thickness of the walls of a shotgun barrel.  It is reasonable to assume that guns built by responsible manufacturers are safe to shoot, when new, with the loads for which they were intended.  As the decades go by, however, as barrels are or buffed for rebluing and as occasional pits are honed out of the bores, steel is gradually removed from the barrels.  The barrel walls, already built thin for lightness, become thinner still.  At some point they become too thin for safety.  It is important to know the barrel wall thickness of an old, well-used shotgun before shooting it.  A rule of thumb states that the minimum barrel wall thickness should be .020" in a 12 gauge gun.

17. bbls - Barrels

18. Beaded cheekpiece - A raised-carved cheek rest on the side of a buttstock, specifically with the extra detail of a shadow line around its perimeter where it blends into the buttstock proper.  Photo

19. Bent - A notch in a hammer or firing-pin housing.  The sear rests in this notch when the firearm is cocked.  When the trigger is pulled, the sear moves out of the bent, allowing the firing-pin to fall under the tension of the mainspring and fire the gun.

20. Bifurcated Lumps - A locking system for over & under guns whereby the barrels are mounted to the receiver via trunnions on either side of the lower barrel and where a pair of bolts move forward into recesses on either side of the barrel-set when the gun is closed.  This system makes it possible to build an over & under gun with a sleeker, lower profile than possible when mounting the lumps, hook, and locking bites to the underside of the bottom barrel.  Boss and Woodward over&under guns are built with bifurcated lumps.  Browning and Merkel over&under guns are built with traditional lumps under the bottom barrel.  Photo

21. Blitz Action - A design where the moving parts of a break-open gun's action are mounted to the trigger plate.  Similar in construction to a Dickson Round Action.  Often seen on German and Austrian guns.  Identified externally by a broader-than-usual trigger plate.  Photo

22. Bolt Action - An action type, most frequently used on rifles, perfected by Peter Paul Mauser in 1898, whereby a cylindrical shaft, controlled by an attached lever, manually feeds a cartridge into the chamber, turns down engaging locking lugs in recesses in the front receiver ring, allows firing by the fall of an internal spring-loaded pin, opening, extraction, recocking and ejection with the same lever in preparation for the next shot.  Photo

23. Bolted Safety - A secondary catch on the safety, often seen on big-bore double rifles, designed to prevent its inadvertent disengagement by a careless gunbearer.  Photo

24. Bore - See Calibre, Gauge, Table

25. Boxlock - A type of action (receiver) for a break-open gun where the lockwork is contained within a box-shaped housing. (see also: Sidelock).  A boxlock is superior to a sidelock because although more metal needs to be removed from the action body, less wood needs be removed from the head of the stock and wood is generally more vulnerable than metal.  The Anson & Deeley boxlock, patented in 1875, the simplest, most reliable and most successful action design, is identified by two pins spanning the width of the action, one at the bottom rear and one slightly forward and higher, upon which the sears and hammers, respectively, rotate.  Photo

26. BPE - Black powder express.

27. Breech - The end of a barrel into which a cartridge is inserted.

28. Bridle - A small secondary plate, mounted behind and parallel to a sidelock gun's lockplate which supports the other end of the pins about which the moving parts rotate.

29. BT or Beavertail Forend - A broad forend, wrapping partially around the barrel(s) to give a more positive grip and to better protect the hand from hot barrels than does a splinter forend.  Photo

30. Bulino Engraving - Shallow, pictorial engraving designs, often of photographic quality, executed directly by hand onto the steel with a fine-pointed scribe called a burin, without the use of a chasing hammer.  Also called banknote engraving.  Often seen on high-grade, contemporary Italian shotguns.  Photo

31. Bushed Firing Pins - Circular steel fittings, about 1/2 inch in diameter, screwed into the breech face of a gun and through which the firing pins pass.  Firing pin bushings allow the convenient replacement of broken firing pins.  They also allow the renewal of an older gun where, over the decades, leakage of high-pressure gas from corrosive primers has eroded the breech face around the firing pins.  In British: Disk-set strikers.  Photo

32. Butt - The end of a gun stock; the part that rests on the shoulder when the gun is mounted.

33. Cal. or Calibre - System of measurement for the internal bore diameter of a rifled-barreled firearm (rifle or pistol) based on the decimal part of an inch.  For example, .25 calibre and .250 calibre both signify a bore size of 1/4 inch.  American calibre designations refer to the distance from land to land, not groove to groove.

34. Carbine - A general term referring to relatively short-barreled, quick-handling rifle.  In Winchester lever-action terminology, a carbine has a single barrel-band.

35. Cast Off - An offset of a gun stock to the right, so that the line of sight aligns comfortably with the right eye while the butt of the stock rests comfortably on the right shoulder.  Almost all right-handed shooters benefit from a little castoff and most custom built guns are made this way.  The only question is how much.  The castoff of a gun is about right when, with the gun comfortably mounted, the front bead lines up with the center of the standing breech.  A stock offset to the left, for shooting from the left shoulder is said to be Cast On.  See Eye Dominance.

36. CC or Casehardening Colors - mottled blue/green/brown colors on a shotgun or double rifle receiver, the by-product of a heat-treating process that incorporates carbon into the surface molecular structure of the steel, providing a hard-wearing surface without making the entire receiver brittle.  The colors themselves are fairly perishable both from wear and from sunlight.  The percentage of original case colors remaining is therefore a quick proxy for the cosmetic condition of the gun.  Photo

Guns should never be rehardened in the vain interest of restoring the cosmetic effect of the colors.  Casehardening is a heat process which alters the surface molecular structure of the steel.  Rehardening an action can warp it.  Subsequent efforts to straighten the metalwork, either by bending or filing will only harm the fine original metal-to-metal fit and adversely alter the workings of carefully aligned internal parts.

37. Chamber - An area at the breech end of a barrel, of about the diameter of the cartridge for which the gun was intended, and into which the cartridge is inserted.  The nominal length of a shotgun chamber will accommodate the loaded cartridge for which it was intended and allow for its crimp to open fully when the cartridge is fired.  Although one can easily insert a longer-than-nominal-length loaded cartridge in a shotgun chamber, it is not advisable to do so because when it is fired the crimp will open into the forcing cone.  Because of the taper of the forcing cone, the crimp will not be able to open fully and the gun will develop far greater pressure than it was designed to handle.
While most 12 gauge shotguns built today have nominal 2 3/4" chambers, this was not always the case.  Prewar American guns and many modern English guns often have shorter chambers.  It is important to know the length of a gun's chambers and to use the ammunition for which it was intended.

38. Checkering - A regular pattern of fine grooves cut into the surface of a stock to aid in gripping a gun.  Originally done for utility only, checkering has become an art form in itself; craftsmen adorning the borders with ribbons, fleur-de-lys, floral carving, etc.  The amount of coverage, the precise regularity, and the number of lines per inch indicate the quality of the work.  Too-fine checkering, however, defeats the purpose of the work altogether.

39. Choke - A carefully measured constriction of the bore of a shotgun at the muzzle, designed to control the spread of the shot as it leaves the barrel.
The descriptions of choke borings are determined by measuring with a bore micrometer, irrespective of any markings on the barrels.  The internal diameter is measured four inches from the muzzle and again just at the muzzle.  Subtracting gives the amount of constriction in thousandths of an inch.
In our descriptions of each gun, chokes are listed in the order of the normal sequence of firing.  Measurements of muzzle constriction by micrometer are useful to predict the pattern thrown by a shotgun barrel, but they remain merely a prediction.  The only way to determine the actual pattern thrown by a shotgun barrel is to shoot it, by convention at 40 yards, count the percentage of pellets falling within a 30" circle placed around the visual center of the pattern, then do it a few more times and take an average.  Table

40. Choke tubes - Short, interchangeable cylinders, of subtly different internal tapers, that screw into a threaded recess at the muzzle of a shotgun.  By inserting different choke tubes, one can alter the shot pattern thrown by the gun.  Choke tubes should be tightened until snug.  Guns fitted for choke tubes should never be fired without tubes inserted.  Photo

41. Chopper-lump bbls(also called Demi-bloc barrels) - A method of joining the two separate tubes of a set of barrels where the right-hand half of the pair of lumps under the barrels are forged integrally with the right barrel and the left-hand half of the pair of lumps under the barrels are forged integrally with the left barrel.  Chopper-lump barrels can be recognized by the fine joint-line running longitudinally down the center of each lump.  This method of jointing barrels is the best because: 1. It is the strongest in relation to its weight, and 2. Because it allows the two barrels to be mounted closest to each other at the breech end, reducing problems regulating the points of aim of the two separate barrels.  Photo

42. Claw Extractor - An essential design element of the Mauser 98 bolt action and its derivatives: the Springfield '03 and the Winchester pre-'64 Model 70.  A large, long extractor is mounted to and revolves around the bolt shaft, or more properly, remains stationary in the receiver raceway when the bolt revolves.  This claw takes positive hold of the cartridge coming from the magazine and places it in the chamber when the bolt is closed.  Then, when the bolt is opened, the claw, never having relinquished its grip on the rim of the cartridge, withdraws it from the chamber with absolute reliability.
Lesser bolt actions have a small clip built into the bolt face which snaps over the chambered cartridge rim when the bolt is closed.  While cheaper to manufacture, this system allows the possibility of the clip slipping back off the rim of the expanded spent case during extraction. Most experienced hunters prefer an action with a Mauser-type claw extractor for its reliability, especially when facing dangerous game.  Photo

43. Claw Mounts - A quick-detachable scope mounting system, popular in Germany and Austria.  The front of the scope is fitted with a hook-shaped tentacle which is inserted into a slot in a fixed front scope base.  The rear of the scope is fitted with another set of hook-shaped tentacles.  When these are pressed sharply downwards into their opposing receptacles they snap into place, held by a spring-loaded clasp, locking the scope into position.  Photo

44. Cocking Indicators - Small devices attached to the internal hammers of a break-open gun and visible from the exterior of the gun to show when each barrel is cocked and when it has been fired.  These are usually in the form of protruding pins on a boxlock gun or in the form of engraved or gold inlaid lines on the tumbler pins of a sidelock gun.  Photo

45. Comb - The top of a gun's stock, where one rests his cheek when mounting a gun.  As it is the top of the stock that determines the position of one's eye, and one's eye is the rear sight on a shotgun, the position of the comb is very important in determining the proper fit of a shotgun.

46. Concealed Third Fastener - An extension protruding rearward from the breech end of a set of side-by-side barrels and entering a complementary recess in the breech face.  The top of the extension is locked down by a cam attached to the toplever spindle.  When the gun is closed this extra fastener is not visible from the exterior of the gun.  Photo

47. Curios or Relics - is defined in 27 CFR 178.11 as follows:

"Firearms which are of special interest to collectors by reason of some quality other than is associated with firearms intended for sporting use or as offensive or defensive weapons.  To be recognized as curios or relics, firearms must fall within one of the following categories:

  1. Firearms which were manufactured at least 50 years prior to the current date, but not including replicas thereof;
  2. Firearms which are certified by the curator of a municipal, State, or Federal museum which exhibits firearms to be curios or relics of museum interest; and
  3. Any other firearms which derive a substantial part of their monetary value from the fact that they are novel, rare, bizarre, or because of their association with some historical figure, period, or event.  Proof of qualification of a particular firearm under this category may be established by evidence of present value and evidence that like firearms are not available except as collector's items, or that the value of like firearms available in ordinary channels is substantially less."
A list of acknowledged "Curios or Relics" is available from the Bureau of Alcohol, Tobacco and Firearms, Firearms Technology Branch, Room 6450, 650 Massachusetts Avenue NW, Washington, DC 20226.

A special Curios or Relics license is available from the BATF, which allows collectors to buy eligible firearms in interstate commerce.  A licensed collector is not authorized to engage in business as a dealer in any firearms, including curios or relics.

48. DA or Double Action - An action type, typical on revolvers, where pulling the trigger through a long stroke revolves the cylinder, cocks the hammer and fires the gun---and alternatively, where manually cocking the hammer and then pulling the resulting single-stage trigger fires it also.

49. Damascus Bbls - Barrel tubes built up by twisting alternate strips of iron and steel around a fixed rod (mandrel) and welding them together in varying combinations according to the intended quality and the skill of the maker.  The rod was withdrawn, the interior reamed and the exterior filed until the finished tube was achieved.  Damascus barrels may be recognized by any of a variety of twist or spiral patterns visible in the surface of the steel.  Before the 20th century, barrels were typically built in this manner because gunmakers did not have the technology to drill a deep hole the full length of a bar of steel without coming out the side.

Damascus barrels were usually intended for use with black powder---the standard of the day.  The contour of the barrel wall thickness, intended for the fast explosion of black powder, was quite thick at the breech and tapered thinner towards the muzzle.  It is not advisable to shoot modern smokeless powder in a damascus barrel.  Apart from giving due deference to the age of such barrels and to the method of their construction, smokeless powder burns more slowly, lowering the pressure at the breech end, but considerably raising it further down the barrel to a level such barrels were rarely designed to handle.  Photo

50. Date Codes -  Chart

51. Deeley Forend Release - A latch for securing the forend to the barrels of a break-open gun, operated by a short pull-down lever mounted to the center of the forend.  Typically seen on Parker and Prussian Charles Daly guns.  Photo

52. Doll's Head - A rib extension on a break-open gun, ending in a circular or semi-circular shape in plan (resembling the head of a doll), mating into a similarly-shaped recess in the top of the receiver, designed to resist the tendency of the barrels to pull away from the standing breech when firing.  Because an action's centerpoint of flexing when firing is at the base of the standing breech, not at the hingepin, a passive doll's head extension makes an effective extra fastener, even without additional mechanical locks operated by the opening lever.  Photo

53. Double Rifle - Two independent rifles, built on one frame, designed to allow two virtually instantaneously quick, totally reliable shots.  The apogee of the gunmaker's art.  Particularly useful against dangerous game, which may be moving, and in your direction, with vengeance on its mind.

54. Dovetailed bbls - The usual way of building a set of side-by-side barrels.  Two raw tubes are filed to approximate their final contour. A solid block of steel is then filed to shape, fitted between the two tubes at the breech end with about 3/4" exposed on the underside and soldered or braised into place to form the lump(s).  see Chopper-Lump Barrels

55. Drilling - A three-barrel gun, typically with two identical side-by-side shotgun barrels mounted above one rifle barrel.  Built primarily in Germany and Austria.

56. Drop - The distance from an imaginary straight line of sight extended along the rib of a shotgun rearward towards the butt---to the top of the stock at the comb or the heel. (In British: Bend).  All drop measurements in listings are taken at the heel; that is, the distance between the imaginary straight line of sight and the stock at its very end.  We will be happy to provide the drop measurement at the comb upon request.
Browning, in its infinite wisdom, considers that 2 3/8" drop at the heel will best fit the broadest range of shooters for field use.  This measurement can therefore be considered "normal".  A gun with less drop will shoot higher, while a gun with more drop will shoot lower for a given individual.  When the gun is comfortably mounted with the cheek snugly on the comb, the drop is about right when you can see the front bead and just a little rib over the standing breech.
Trap guns usually have less drop because they are supposed to shoot a little high in order to hit an almost universally rising target.  Standard wisdom indicates that the drop is about right for a mounted trap gun when the front bead seems to rest just on top of the middle bead like two parts of a snowman, or forming a figure-eight.

57. DST or Double Set Trigger - On a rifle, optionally pulling the rear (set) trigger converts the front (main) trigger to a light, hair trigger.  While the front trigger is always at the ready, if one has the time, using the set trigger feature may allow for a more accurate long-distance shot.  Operates using its own miniature firing mechanism (sear, spring and hammer) when cocked, to multiply the force of a pull on the main trigger.  Photo

58. DT or Double Triggers - one for each barrel.  Double triggers are better than single triggers on a double gun because: 1. They are simpler in design, therefore making the gun lighter and more reliable. 2. They are less prone to double-firing. 3. In the hands of an experienced shooter they are faster. 4. They allow immediate selection of which barrel to fire - the immediate selection of the pattern to throw - even while the grouse is flushing.

59. Ejectors - Fittings inset into the breech end of a pair of barrels of a break-open gun that kick out fired shells, while only raising unfired shells enough to be removed by hand.  Recognizable at a glance on the breech end of a double gun because the fitting is split in two---one ejector for each barrel.  Photo

60. Elevation - Adjustment of the point of impact of a firearm in the vertical plane; the knob used on an iron sight or telescopic sight to raise or lower the point of impact.

61. Energy - Capability to perform work.  As measured in foot-pounds, the amount of force it takes to lift and object weighing one pound, one foot.  To calculate the energy, in foot-pounds, of a bullet in flight at any point on its trajectory:

W
WV2 W = Weight of the bullet in grains.
V = Velocity in feet per second
450436

62. English Grip - A straight-wrist grip, typical on English shotguns, built for graceful aesthetics, light weight and fast handling.  Photo

63. Express Sights - "V" shaped rear leaf sights mounted to a rifle barrel on a block or on a quarter-rib, sometimes solid standing, sometimes folding, and often mounted in a row of similar leaves, each of a slightly different height, marked with the range for which each is regulated.  Photo

64. Extractors - A fitting inset into the breech end of a pair of barrels of a break-open gun.  When the gun is opened the extractor lifts the cartridges so they may be removed by hand.  Recognizable at a glance on the breech end of a double gun because the fitting is solid---one extractor taking care of both barrels together.  Photo

65. Eye Dominance - Although we have two eyes for depth perception and for spare parts, there is a natural tendency for one eye to take precedence over the other, regardless of the relative visual acuity of each eye.  It is a fortunate condition when the eye on the side of the shoulder where one is comfortable mounting a gun is also the dominant eye.

To test for eye dominance, pick out a small object several feet away.  With both eyes open, center your right index finger vertically over the object.  Close your right eye.  If your finger appears to jump to the right, you are right eye dominant.  Then open your right eye and close your left eye.  If your finger remains in position in front of the object, you have confirmed your right eye dominance.  Alternatively, if in the above test, upon closing your right eye your finger remains in position covering the object, you are left eye dominant.  If you close your left eye instead and your finger appears to jump to the left you have confirmed your left eye dominance.

Eye dominance problems can be treated with 1. A severely-cast, crossover stock to bring the dominant eye in line with the gun's line of sight, 2. A patch over the dominant eye, or just a small piece of frosty Scotch tape on shooting glasses intercepting the dominant eye's line of sight, 3. Fully or partially closing the dominant eye, or 4. Learning to shoot from the dominant-eye shoulder.  While less convenient, methods that retain the use of both eyes better preserve the ability to perceive depth in three-dimensional space---a great benefit in wingshooting.

66. Fences - Hemispherical outgrowths of the receiver of a double gun that mate with the breech ends of the barrels.  The term derives from the flanges (or fences) in this position on a muzzle loading gun that were designed to protect the eyes of the shooter from sparks and escaping gasses.  Photo

67. FFL - Federal Firearms [Dealer's] License.

68. Field Forend - A relatively slender forend on an over & under gun (as opposed to a beavertail forend).  Over & Under counterpart of a Splinter Forend.

69. Figured Walnut - Every piece of walnut is different in terms of its figure or fancy, streaked, fiddleback, burled, grain pattern.  It is difficult to describe a beautiful gunstock in a couple of words, but we use the following terms:


[No mention]

Plain wood, perhaps with visible grain but without swirls.  Straight and strong.
Lightly figured walnut Some figure to elevate it from the ordinary.
Figured walnut Very pleasing figure, covering about half the buttstock.
Highly figured walnut Beautiful figure, covering virtually all the buttstock.
Exhibition walnut Stunning figure, dramatically covering the entire stock. We rarely use this term.



70. Floated barrel - A rifle barrel mounted firmly to the receiver, but not touching the forend.  Done so that the stock will not adversely effect accuracy by impinging upon the natural vibration of the barrel when the rifle is fired.

71. Fluid Steel bbls - Barrels made of homogeneous steel (not damascus steel) --- standard practice for a century.

72. Forcing cone - A tapered area providing a transition between the chamber of a shotgun (approximately the diameter of the outside of a shotgun shell) to the bore proper (approximately the diameter of the inside of a shotgun shell).  Older shotguns usually have more abrupt forcing cones suitable for then-current thick-walled paper shells with fibre wads.  Newer shotguns usually have more gradual, longer forcing cones suitable for thinner modern plastic shells with obturating plastic shot-cup wads.

73. Full Stock - A rifle or carbine with a one-piece stock extending to the muzzle.  Sometimes called a Mannlicher stock, although such a term is confusing because Mannlicher Schoenauer rifles are built with both full and half stocks.  Traditional in Europe for close-range woodland hunting, but not noted for extreme, long-range accuracy.

74. Gauge - System of measurement for the internal bore diameter of a smooth-bore firearm based on the diameter of each of that number of spherical lead balls whose total weight is one pound.  The internal diameter of a 12 gauge shotgun barrel is therefore equal to the diameter of a lead ball weighing 1/12 pound, which happens to be .729" (Or in British: Bore.) The Gauge/Bore system is also used, by convention, to describe the internal barrel diameter of large-bore, 19th century, English, single-shot and double-barrel rifles.  Table

75. Glassbedding - Swabbing wet epoxy over the inletted portion of a stock, covering the metalwork with a release agent and pressing the barreled action into the wood.  A process undertaken to compensate for imperfect wood-to-metal fit.

76. Gloaming Sight - A second, folding or pop-up front sight bead of larger than usual size, perhaps not as accurate as a normal fine bead, but easier to see in the gloaming (twilight) or dawn.  Photo

77. Globe Sight - A front sight assembly, primarily for target rifles, consisting of a tube, housing interchangeable beads and blades.  The tube protects the actual sight blades from reflection.

78. Greener Crossbolt - A tapered round bar, operated by the toplever of a shotgun, passing transversely behind the standing breech of a side-by-side gun and through a matching hole in a rib extension; to strengthen the lock-up.  Scott's crossbolt operates similarly, but is square in cross-section.  Photo

79. Greener Safety - A safety catch mounted to the left side of a gun, just behind the receiver, which swivels fore and aft on a transverse rod.  Often seen on drillings as well as on Greener's own shotguns.  Photo

80. Hand-Detachable Locks - The firing mechanism of a break-open gun which may be removed for inspection or cleaning without the use of tools.  The release latch may be plainly visible or concealed.  A feature typically seen on sidelock guns but also on the Westley Richards "droplock" boxlock action.

81. Headspace - The distance, or clearance, between the base of a chambered cartridge and the breech face (or bolt face) of a firearm.  This is a critical dimension, particularly in high powered rifles.  If there is too little headspace, the bolt will not close.  If there is too much headspace the cartridge will not be properly supported in the chamber and the cartridge will expand upon firing and may rupture, blasting high-pressure gas into the action and possibly the body of the shooter.  Headspace should be .003" - .006" in a centerfire rifle.  It can be measured with a set of "Go and No-Go" gauges specific to the calibre in question.

82. Heel - The top of the butt-end of a gun stock.

83. Hinge Pin - A short cylindrical rod of hardened steel running laterally near the front of the bar of a break-open gun's action around which the barrel hook revolves when the gun is opened.  Over the decades, this pin and its complimentary hook can wear and a gun can sometimes "shoot loose" or "come off the face".  The proper cure for this condition is to replace the hinge pin with a new one, slightly oversized, to compensate for wear on both itself and on the barrel hook.

To test for a worn hinge pin, remove the forend (which helps hold the barrels tightly onto the receiver).  Hold the receiver in one hand and the end of the butt in the other.  Give the gun a good shake, side to side.  If you can detect movement of the barrels against the receiver, the gun has probably see n a good deal of use.  It probably ought to have a new hinge pin fitted by a competent gunsmith.

84. Holdopen Toplever - A catch built into the receiver of a break-open gun to keep the toplever in its extreme right position when the barrels are removed.  This device makes it slightly easier to remount the barrels.  When the barrels are mounted and the breech closed, the toplever automatically returns to the center locked position.  As, however, it requires a separate act to re-center the toplever on a broken-down gun, this feature may be irritating when trying to put a gun away in its case.

85. Imports - Click for information for foreign sellers and for Americans purchasing firearms abroad.


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86. Intercepting Sear - A second sear, poised just behind a second notch in the hammer.

It is possible that when a cocked firearm is dropped or sharply jarred, a single sear could jump out of its notch and the hammer could fall, firing the gun accidentally.  In this event, an intercepting sear would engage before the hammer could fall completely, preventing an accidental discharge.  On a gun with intercepting sears, only by pulling the trigger are both sears moved out of the way simultaneously, allowing the gun to fire.

Intercepting sears are usually found on better sidelock actions.  They are sometimes found on best boxlocks, and can be recognized by an extra screw behind the action fences, in addition to the usual two screws (or pins) along the lower rear of the receiver.

87. Jeweled - An engine-turned treatment on a steel part done both for a finished look and to hold oil on the surface.  An abrasive-impregnated rubber bit is used to describe a circular pattern on the surface of the steel, then moved just a little less than distance of the diameter of the bit, touched to the surface again, and the process repeated until the steel surface is covered with small regular rows of circular swirls.  Photo

88. Jones Underlever - A lever, mounted to the underside of the receiver of a break-open gun, extending half way around the trigger guard and ending in a knob the shooter can grasp.  When the lever is turned 90 degrees to the right, a pair of tapered, opposing lugs move out of mating bites in the barrel lumps, allowing the barrels to drop open on the hingepin.  While not the fastest-opening design for the lockup of a break-open gun, it is arguably the strongest.  Photo

89. Kersten lock - A crossbolt running laterally, just behind the breech face, through the top of the standing breech of a break-open gun which passes through a complimentary hole in a flange extending rearward from the top side of a barrel.  Double Kersten locks: two such locks, one on either side of the barrel set.  A system of lockup usually found on German over & under shotguns such as Merkel and Simson.  Photo

90. Leaf Sights - Folding blade sights, similar to express sights, but hinged essentially from one position instead of in a long row.  Photo

91. LTRK - Long tang, round knob, semi-pistol grip (Browning).

92. Lumps - The projections extending downward from the breech end of a side-by-side gun.  Into the lumps are machined the hook (to swivel around the hingepin) and the bites (to accept the locking bolts).  Also called underlugs.  Photo  See also Bifurcated Lumps and Chopper Lumps

93. Mag. or Magnum - A marketing term for a cartridge of greater than normal power or velocity.

94. Minute of Angle - A 1/60th part of a degree, the unit of measure used in adjusting rifle sights.  As it turns out, a minute of angle translates almost exactly to one inch at 100 yards, to two inches at 200 yards and three inches at 300 yards.

95. Monoblock bbls - A method of building a pair of barrels where the entire breech end of both barrels and the lumps together are machined from one solid piece of steel.  The barrel tubes are then fitted separately into this monoblock and the ribs attached.  Often identifiable by a distinctive ring around the barrels about three inches in front of the breech end.  The favored jointing method of the Beretta company.

96. Monte Carlo Comb - An elevated gunstock comb which drops to a normal height at the heel.  Useful on rifle stocks to align the eye with a telescopic sight better, and on trap guns to raise the point of impact.

97. Monte Carlo Cheekpiece - A cheek rest, built onto the side of a gunstock, which also extends upward to raise the comb of a stock, then falls sharply to a normal height so as not to affect the drop at the heel.  As above, useful on rifle stocks to align the eye with a telescopic sight better, and on trap guns to raise the point of impact.  Photo

98. Muzzle - The end of a barrel, pointing towards the target, out of which the load is discharged.

99. Muzzle Brake - A fitting attached to the muzzle of a firearm, with a series of perforations designed to deflect some of the forward-rushing gasses and pull the firearm forward off the shoulder, reducing recoil.  While muzzle brakes can be effective in reducing recoil, their resultant blast is at least mildly offensive to anyone else standing nearby.  Photo

100. NE or Nitro Express - A big-game cartridge, powered by nitro-glycerin-based propellant, "as powerful as an express train."

101. New - New from the manufacturer or distributor.  Never sold at retail.

102. NIB - New, unfired, in original box, although possibly previously owned.

103. O/U or Over and Under [barrels] - Over and under barrels are better than side-by-side barrels because they have a narrower sighting plane.  They allow more precise aiming and allow slightly better peripheral vision.  Over & under guns are more suitable for shooting clays, where one generally knows where and when the target will be presented.  Consider the analogy that fine crosshairs in a rifle scope may be harder to see, but when one has time, allow for a more accurate shot than the broad crosshairs of a hunting scope.

104. Oval - A small oval plate of nickel, silver or gold, usually inletted flush into the underside of the buttstock of a fine gun on which the owner's initials, monogram or coat of arms my be engraved.  Also: escutcheon.  Photo

105. PG - Full Pistol Grip, with flat knob, with or without pistol grip cap.  Although less sleek in appearance than a straight English grip, a more naturally fitting handle allowing the human hand to hold the gun in a more relaxed position.  Photo

106. Pitch - The angle of the butt of a gun in relation to the line of sight.  In America, pitch is measured by resting the gun with its butt flat on a floor, the top of the receiver against a wall and its muzzle pointing up.  The distance of the muzzle from the wall is the gun's pitch down.  In England, pitch is determined by measuring the length of pull, separately, to each of the heel, the middle of butt and the toe.

107. Ported barrels - Barrels with a series of holes or slots drilled near the muzzle.  When a ported barrel is discharged, gasses moving violently down the barrel hit the forward edge of the holes and pull the gun forward off the shoulder, reducing felt recoil.  Porting holes, when cut along the top of the barrel also work to depress the barrel under discharge, counteracting muzzle jump.  Ported barrels may provide some benefit to the shooter, but the sideways blast of gas is somewhat obnoxious for others nearby.

108. Prewar - Before World War II (with all due respect to those who served in other conflicts).

109. Proof - The test-firing of a gun with an extra-heavy load, at an official establishment, to verify the safety of a gun, which is then marked with formal stamps showing, among other things, the loads for which it is intended.

Most civilized countries have proof houses, run either by the government or by the trade association under the regulation of the government.  In these countries, every new gun must pass proof before it is sold.  The United States, the most litigious country in the world, has no proof house.  Perhaps for these reasons, American shotguns are often stronger and heavier than their European counterparts.

110. Pull - The length of a stock, as measured from the center of the trigger to the center of the butt.  Pull measurements are not exactly comparable between double-trigger and a single-trigger guns.  The length of pull is about right for a shotgun when, with the gun comfortably mounted, there are about two finger-widths between the meat of your thumb and your cheekbone.  Any less, and you might hit your face with your hand when the gun recoils.  Any more, and you might catch the butt on your clothing when you hastily mount the gun.

111. Purdey Underbolts - A sliding bar, running longitudinally through the watertable of a break-open side-by-side gun's action, with openings through which the lumps of the barrels pass when the gun is closed.  Under spring tension, this bar moves forward when the opening control is released and its two locking surfaces engage complementary slots (bites) in the rear of the two barrel lumps.  Originally operated by a hinged tab in front of the trigger guard.  Now invariably operated by a cam from Scott's [toplever] spindle.  Most modern side-by-side guns lock closed in this manner.  Photo

112. QD - Quick-detachable, as in scope mounts or sling swivels.

113. Receiver - The frame or action body of a firearm.  The housing that contains the mechanism that fires the gun.  The serially-numbered part which legally constitutes the firearm.

114. Regulation of Double Rifles - If the two barrels of a double-barrel shotgun shot 3" apart at 25 yards, not many people would notice because the pattern from each barrel, spreading two feet across at that range, would largely overlap.  If, on the other hand, the two barrels of a double rifle shot 3" apart at 25 yards, it would probably shoot 6" apart at 50 yards and 12" apart at 100 yards, limiting its utility.

One cannot build a double rifle, using sophisticated mass-production machinery with barrels perfectly parallel and expect both barrels to shoot to a common point of impact.  While the bullet is travelling down the right barrel (of a side-by-side double rifle) the rifle will be pushed up and to the right, throwing the bullet up and to the right when it exits the muzzle.  While the bullet is travelling down the left barrel, the rifle will be pushed up and to the left, throwing the bullet up and to the left when it exits the muzzle.  To compensate for the movement of a double rifle while bullets are travelling down the barrels, it must be built with the barrels converging towards the muzzle (by a mysterious amount).  Because different powder charges, bullet weights, rifle weights, shooter body weights, ambient temperatures, etc., all effect the way a rifle moves under recoil, the only way to balance these factors is by trial and error.  This process is called regulation.

The goal of regulation is to make the rifle shoot both barrels to a common point of impact at a range appropriate for the calibre.

One can proceed generally in either of two ways: adjusting the relative position of the barrels or adjusting the load.  If one has a fixed load in mind, the former method must be used.  It involves repetitive unsoldering and resoldering the barrels until the required convergence is achieved, then relaying the ribs and finally refinishing the barrels.

A simpler method is to vary the load.  The longer the bullet spends travelling down the barrel, the greater the force is exerted on the rifle to cause it to move while under recoil.  If bullets from the left and right barrels strike the target too far apart at the desired range, and have crossed before they reach the target, the velocity is too great.  The bullet weight must therefore be increased or the powder charge decreased.  If bullets from the left and right barrels strike the target at the desired range too far apart, but have not crossed before they reach the target, the velocity is too slow.  The bullet weight must therefore be decreased or the powder charge increased.

The construction of an effective double rifle is the apogee of the gunmaker's art.  If, however, one comes into possession of a double rifle for which the original load is unknown, one can often make it shoot well by adjusting the load to the rifle.

115. Reinforcing Crossbolt - A steel bolt, mounted transversely through a rifle stock just under and behind the front (and sometimes rear) receiver ring, sometimes concealed in the wood and usually against which the action is carefully bedded.  When properly fitted, it helps distribute the recoil and reinforces stock at the point where wood has been removed to accept the action.  Reinforcing crossbolts can be recognized by the flush-mounted circular steel fittings on the side of the stock, but are sometimes finished with contrasting wooden plugs and sometimes concealed completely.  Also called Recoil Crossbolt.  Photo

116. Release Trigger - A trigger mechanism which sets when pulled, and then fires when released.  Sometimes fitted to competition shotguns for shooters who are bothered by flinching, but perilous in the hands of someone not expecting such an arrangement.

117. Rifle - A relatively long-barreled firearm, fired from the shoulder, having a series of spiral grooves cut inside the barrel that impart a rapid spin to the single projectile, stabilizing it in flight for greatly improved accuracy over that of a smoothbore gun.

In cross-section, Enfield rifling is composed of a series of square-edged lands and grooves while Metford rifling has slightly rounded lands and grooves.

118. Rifle Cartridge Designations - Although proprietary variations abound, a few general principles follow:

19th Century American: Calibre in inches - Grains of black powder - (and sometimes weight of bullet in grains). i.e. .30-30 means a .30 calibre bullet driven by 30 grains of black powder.

European: Diameter of bullet in millimeters by length of empty case in millimeters. i.e. 7x57 means a 7mm diameter bullet loaded in a 57mm long case.  An "R" suffix denotes a rimmed cartridge.

Vintage English: The basic case diameter - the neck diameter, then the case length. i.e. .450-400 3 1/4" means a .450" diameter case, necked down to .400" 3 1/4" long, unloaded.

119. Rolled Triggerguard - A thickened, beaded edge on the side of a triggerguard bow.  This extra detail allows the triggerguard to be made light, thin and graceful while at the same time thick enough to avoid finger injury when the gun recoils---theoretically possible with a sharp-edged triggerguard.  Photo

120. Rook Rifle - English term for a light, usually single-shot rifle, firing a centerfire cartridge of power similar to a pistol cartridge, and used to shoot rooks, crows and other vermin.

121. Rose & Scroll Engraving - A traditional English engraving pattern where areas of tight scroll are interspersed with bouquets of roses.  This pattern developed as much to impart a texture to the raw polished steel which would remain after the color hardening had worn off, as it was an art in its own right.  Photo

122. Scalloped receiver - Extra detail on a boxlock gun where the rear edge of the receiver is carved into any of a variety of curved shapes where it joins the buttstock instead of being left in a simple straight vertical line.  Also called Fancy-back.  Photo

123. Schnabel - Stock detail, typical of German and Austrian rifles, where the forend tip flares out to an enlarged knob.  Photo

124. Scope Blocks - A pair of small dovetailed steel bases, screwed usually one to the barrel and one to the front receiver ring of a rifle, to accept mounts for target scopes such as the Unertl where the scope is allowed to move forward in the rings under the recoil of the rifle and which typically carry the windage and elevation adjustments in the mount.  Photo

125. Sear - A sharp bar, resting in a notch (or in British: "bent") in a hammer (or in British: "tumbler"), holding the hammer back under the tension of the mainspring.  When the trigger is pulled, the sear moves out of its notch, releasing the hammer and firing the gun.

126. Self-Opening (Assisted Opening) - Attribute of a break-open gun whereby the barrels drop down simply by pressing the toplever without muscling them open manually.  The Holland & Holland system utilizes a coil spring within a cylindrical housing mounted just ahead of the forward lump to urge the barrels open.  The Purdey system utilizes residual energy remaining in the mainspring after the gun has been fired.  Both systems enable a shooter to load quickly when birds are coming fast.  Photo

127. Shot Sizes -  Table

128. Sideclips - A pair of small beveled flanges extending forward from the sides of the standing breech of a shotgun, mating with similarly beveled edges of the breech end of the barrels; reinforcing the barrels against lateral movement while firing.  Photo

129. Sidelock - A type of action on a break-open gun where the lockwork (hammer, sear, mainspring etc) is mounted to the back side (inside) of a plate (or pair of plates for a double gun).  A sidelock is superior to a boxlock because: 1. Less steel needs be removed from the bar of the action; the action is therefore stronger. 2. The lock plates provide a larger canvas for the engraver's art. 3. Sidelocks have generally been considered a more aesthetically pleasing form. 4. They are often made with secondary, or intercepting, safety sears. 5. Trigger pulls theoretically may be adjusted more precisely. 6. Because of all the above, most makers building a range of guns have usually reserved the sidelock action for their better grades of guns; this last being the most relevant reason why sidelocks are generally considered superior to boxlocks.  Photo

130. Sideplates - Decorative steel plates mounted to the sides of a boxlock break-open gun, inletted into the receiver and into the wood just behind it, to make the gun resemble a sidelock in appearance and to provide a greater area for engraving.

131. Single Action - An action type, typical on revolvers, where the hammer must be cocked manually prior to each shot.

132. Single Set Trigger - A single trigger, operating at a normal 4 - 6lb pull, which when pushed forward converts to a hair trigger.  This trigger is usually fitted with a small set screw to adjust the weight of the hair trigger.

133. Skeet tubes - Interchangeable sub-calibre, full-length liner tubes that fit into the barrels of a shotgun to reduce the gauge without using a different gun or a different barrel set.  Skeet tubes allow one to shoot the required different gauges in competition skeet without having to invest in a set of guns, invest in extra sets of barrels or adjust to using different guns.  Photo

134. Sleeved bbls - An economical method of bringing new life to a damaged pair of barrels, regardless of their original method of jointing.  The ribs are removed.  The barrels are cut off 3" - 4" from the breech end and discarded.  The bores of the remaining breech-end are reamed out oversize.  New tubes are fitted down into the original breech section and filed down to fit flush.  The original ribs are then replaced.

Sleeving is considerably less expensive than building a completely new set of barrels.  Much of the time required to build a set of barrels is concentrated in the fitting of the breech end to the receiver; this work is salvaged through sleeving.  Sleeving can be recognized by a pair of circumferential lines around the barrels a few inches from the breech; the more invisible, the finer the job.  A sleeved gun should always be identified as such amongst the proof marks, and if done in England must be properly reproofed.

135. Snap Caps - Dummy cartridges with spring-loaded "primers" used to test the mechanical functioning of a firearm, particularly the hammer-fall and ejector-timing of a break-open gun.  It is not advisable to dry-fire a break-open gun on an empty chamber.  Hardened steel parts can shatter without the soft brass primer to act as a shock absorber.  Snap caps cushion the blow of the hammer and firing-pin when the use of a live cartridge would be impractical.

136. spl or Splinter Forend - A slender English-style forend on a break-open gun, designed to retain the barrels on the receiver when the gun is opened and to house the ejectors---not necessarily to provide a hand-hold.  Splinter forend guns are more properly grasped by the barrels just ahead of the forend.  The closer one's hand is to the line of the bore and to the line of sight, the better one's coordination.  Many people consider the splinter forend more graceful than a beavertail forend on a classic double gun.  Photo

137. SRC or Saddle Ring Carbine - A carbine with a ring fitted to the side of the receiver.  Such a firearm may be attached to a saddle with a lanyard.

138. SST or Single Selective Trigger - A single trigger with some sort of switch to change the order of firing of a pair of barrels.

139. ST - Single [non-selective] Trigger - Single triggers are better than double triggers because with the trigger always in a constant position one does not even have to consider changing one's hand position and because there is one less thing to think about when concentrating on the target.  A single trigger is usually easier for people used to pump, semi-automatic and bolt-action guns.  A plain single trigger is simpler and usually more reliable than a selective single trigger.

140. Stalking Safety - A safety catch fitted to a hammer gun where a sliding bar moves into a slot in the inner wall of the hammer base, locking it in place in the cocked position.  The safety can then be released silently by sliding the tab, avoiding the game-startling sound of the hammer cocking.  Photo

141. Steel Shot - Shotgun shot pellets of steel, designed as a non-toxic substitute for traditional lead shot.  Unlike lead, steel pellets do not deform as they pass through the choke of a shotgun barrel.  Steel shot should not, therefore, be fired through a tight choke (anything more than .015" constriction in a 12 gauge) or greater pressure will be generated than the gun was designed to handle.  The result will be a ring bulge near the barrel's muzzle.  Thankfully, also because steel pellets do not deform, fewer pellets are lost from the bulk of the pattern so steel shot patterns more tightly than lead.  Although steel shot has less specific gravity than lead and therefore does not carry as far, within its effective range less choke constriction is needed for steel shot to achieve the same pattern density as lead.  Click for relative physical characteristics of lead and steel shot.

142. STFK - Short tang, flat knob pistol grip (Browning)

143. STRK - Short tang, round knob, semi-pistol grip (Browning)

144. Str or Straight English-style grip - Generally considered sleeker and more aesthetically pleasing than a pistol grip.  It helps reduce the weight of a gun.  Some consider it faster to use in field-shooting situations.  Photo

145. SxS or Side by Side (barrels) - Side-by-side barrels are better than over & under barrels because they have a broader and more quickly-acquired sighting plane.  Although one should always concentrate on the target and not the gun, in field shooting, having subliminal consciousness of the position of the barrels is a real aid to throwing the shot towards a suddenly-appearing moving target.  Although not as precise, it is quicker to find the broad crosshairs of a hunting telescopic sight than the fine crosshairs of a target scope.  Side-by-side guns are easier to load than over & under guns because the barrels do not need to be opened to as wide an angle (gape) for cartridges to clear the standing breech.  Side-by-side guns traditionally have been considered more elegant of line than over & under guns.

146. Takedown - A firearm design whereby the barrel(s) is/are easily removed from the action without the use of tools.  This arrangement allows for more convenient transportation of a firearm, but with rifles, at a small sacrifice in accuracy.

147. Teardrops - Small, raised-carved details on either side of a double gun, behind the lockplates of a sidelock or behind the flat sidepanels of a boxlock, in the shape of teardrops.  Also called dropper points.  Photo

148. Throat - The beginning of the bore of a rifled firearm.  The transition between the chamber and the rifling.  The area most vulnerable to erosion from high velocity cartridges.

149. Toe - The bottom of the butt-end of a gun stock.

150. Tumbler - British for Hammer.

150. Tunnel Claw Mount - A claw [scope] mount with openings through which a shooter can use a rifle's iron sights without removing the scope.

151. Type of Grips - Round knob, semi pistol grip (Prince of Wales grip).  Photo

152. Vierling - A four-barreled gun, typically with two identical shotgun barrels and with two rifle barrels of differing calibres.  Built primarily in Germany and Austria. Rare.

153. VR or Ventilated Rib - Designed to help cool and more particularly to direct the shimmering hot air that rises from hot barrels away from the line of sight in order to reduce disturbance in the view of the target.  Ventilated ribs are useful on target guns, but less desirable on field guns where small twigs and other detritus can become lodged in the openings under the rib.

154. Watertable - The top of the bar of the action, the flat projection on the front of the receiver of a side-by-side gun, perpendicular to the standing breech.  The cocking arms, hingepin and locking bolts are typically mounted inside the bar, below the watertable.

155. Windage - Adjusting the point of impact of a firearm in the horizontal plane; the knob used on an iron sight or telescopic sight to move the point of impact in traverse, right or left.

156. Wrist - The thinnest section of the stock of a long gun between the receiver and the butt, gripped by the trigger-hand.  The most vulnerable part of a gunstock.

157. Wundhammer Swell - A bulge in the side of the pistol grip of a stock designed fill the palm of the hand and offer the shooter a more comfortable, repeatable hold on his gun.  Palmswell. Named for the American gunsmith who promoted it.


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