It is said to be a fact that the proof marks of both companies are forged and imitated, both in England and in Germany, and many cheap guns so stamped are exported to this country. A cheap gun, with the stamps mentioned, may be looked upon with suspicion as to its really having been in the official proof-houses.

The proof marks employed by the inspectors in the U. S. Government armories, and placed on all arms inspected by them, even if made in private armories, are V for viewed, and P for proved, together with the initial letters of the inspector’s name, and are found stamped on each barrel. On many guns of the old model arms will be found, in addition to these marks, the head of an eagle. This is the mark that indicated that the barrels were made at the armory at Harper’s Ferry, when those works were in operation.

Gauge of Gun Barrels.—Guns are gauged by numbers, and these numbers were originally designed to express the number of round balls to the pound that would fit the bore of the barrel. Thus a ten gauge, a ball of which ten made a pound, would fit the bore, etc. Ten and twelve bores are generally used by sportsmen, especially those who use breech-loaders. The twelve, perhaps, is the one most employed.

The following list shows the sizes of various gauges, the values of the numbers being those adopted by the English proof companies. The diameters of bores being expressed in decimal thousands of an inch:

Number
of
Gauge.		Diameter
of bore
in inches.
11.669
21.325
31.157
41.052
5.976
6.919
7.873
8.835
9.803
10.775
11.751
12.729
13.710
14.693
15.677
16.662
17.650
18.637
19.626
20.615
21.605
22.596
23.587
24.579
25.571
26.563
27.556
28.550
29.543
30.537
31.531
32.526
33.520
34.515
35.510
36.506

Muzzle-loaders are of almost every variety of gauge, while breech-loaders are made of a limited number of sizes. The sizes of this class of guns are 8, 10, 12, 14, 16 and 20, and are limited to these sizes, there being no intermediate sizes. The 10 and 12 bore are mostly in use, the 12 being in especial demand. The calibre or bore of military guns during the Revolution was 75 hundredths of an inch, and has been reduced by successive stages until now it is but 45 hundredths. Down to 1856 the calibre of the Springfield musket was 58 hundredths. In 1856 it was changed to 50 hundredths or one-half inch; and again, in 1873, it was changed to the present calibre of 45 hundredths.

Bursting of Barrels.—Bursting of barrels may result from three causes: Poor quality of iron of which the gun is made; an excess of charge; or some obstruction in the barrel so as to form an air space between the charge and the obstruction. Of poor quality barrels, and excess of charge it is needless to make mention. The instances of bursting from obstructions forming the air space or chamber may be mentioned in military guns, firing the charge but neglecting to remove the wooden tompion from the muzzle of the gun. In sporting guns snow may accidentally get into the muzzle or a lump of dirt may “somehow” get in so as to fill the bore, and when the gun is fired, it will probably, yes, most certainly be blown off or blown open where the obstruction exists; the muzzle of a gun being thrust into water for a couple of inches or more will have like effect. The gas formed by burning the powder finds no outlet of escape, and the whole expansive force concentrates itself on the weakest portion of the barrel, and as a result it is forced apart. In good guns the portion toward the muzzle is the thinnest, and obstructions are generally at or above this place, and it is in this proximity where most guns are burst. If within three, four or five inches from the muzzle, the portion so destroyed can be sawed off, the barrels squared up and it will not always seriously affect the shooting of the gun.

In loading a gun be careful that there be no air space left between the charge and the ball or shot cartridge. In double guns, frequent firing the right barrel, which is the one fired the most, the recoil will often cause the ball or shot charge in the left barrel to be thrown forward from the powder, and when it is fired may either strain or burst the barrel. Even if there be a small air space between the powder and the ball or shot cartridge it will affect the shooting. Every one using double guns should accustom himself to the use alternately of both barrels, not only for safety but for good shooting. A barrel is often said to be a poor shooter, when its bad qualities may be wholly ascribed to the air space produced above the powder by the recoil occasioned by firing the other barrel.