IN passing from rifles to shotguns, we encounter a quite different set of problems. Still, the two arms have this much in common, that all depends upon what we want to do with them. Some kinds of gunning require a wide spread of shot at close quarters; others, a compact swarm at a considerable distance. Some game can be killed with small shot; other game requires large pellets. The more pellets we use, the better chance of hitting, but the more lead thrown, the heavier our gun must be. Charge of powder and shot must be proportional to weight of gun, and weight governs dimensions.
Let us take up one point at a time, keep our minds on it for the time being, and not be over-hasty about drawing conclusions. In the end, we shall find that desirable qualities conflict, more or less, and that compromises between them must be made, lest we pick out a freak gun that excells in some one merit at the expense of others.
The power of a shotgun is determined by its pattern and penetration. Pattern means two things.
1. The percentage of shot pellets that the gun will place in a given area, at a given distance, the standard being a thirty-inch circle at forty yards;
2. The evenness with which the pellets are distributed over that area.
An ideal pattern would be one containing every pellet of the charge, all spaced equidistant from each other. But no gun ever shoots that way. Many pellets are battered out of shape by concussion, or by friction against the bore. Since these offer unequal surfaces to the air's resistance, they soon swerve like a flat stone. Others are jostled out of the way by their crowded neighbors.
The pattern that a charge of shot will make depends very much upon how the gun barrel is bored. When shot are fired from a true cylinder they soon scatter widely, so that only thirty per cent to thirty-five per cent of the pellets will strike inside a thirty-inch circle, at forty yards. This is too thin a pattern for any but the shortest ranges; consequently guns are not bored to a true cylinder for sporting purposes. What are called " plain cylinders " by the trade are really made with a slight taper toward the muzzle, which compresses the charge enough to pattern, on the average, about forty per cent. Try your 12-gauge " cylinder " and see if it is not about 13-gauge at the muzzle.
To produce still closer patterns, the gun bore must have a rather abrupt choke (constriction) near the muzzle, so as to jam the shot together at the instant of leaving the gun's mouth. The fuller the choke, the denser the pattern. A quarter choke (sometimes called "improved cylinder ") averages about fifty per cent of the charge in a thirty-inch circle, at forty yards; a half or " modified " choke, about sixty per cent; a full choke, about seventy per cent; an extreme choke, from seventy-five to eighty per cent. These, at least, are the definitions that I shall follow. Gun-makers disagree a good deal among themselves in the meaning they give to such terms as cylinder, open bore, modified choke, full choke, etc. It would be better to discard such words altogether and describe the degree of constriction by the percentage of charge that the gun patterns at forty yards. A " full choked " gun is simply one that patterns about seventy per cent, regardless of its gauge and other dimensions. It may take a constriction of 0.04 inch to full choke a 10-gauge, and only 0.02 inch to full choke a 20-gauge, but both guns will throw the same percentage of their charges (say seventy per cent) into a thirty-inch circle at forty yards. Length of barrel has nothing to do with this.
Spread of charge depends largely upon choke. A full choke (seventy per cent) gun throws the effective part of its charge into a thirty-inch circle at forty yards; a half choke into a thirty-six inch circle; a quarter choke into a forty-two inch circle; a " cylinder 99 into a forty-eight inch circle. This is true of all gauges alike, notwithstanding what you may have been told to the contrary.
Different chokes are adapted to different purposes. It is with shotguns just as it is with rifles. No one gun can excell in all kinds of shooting. When one is hunting ruffed grouse in the woodlands, the game springs up from concealment with a whir-r-r, and it must be downed at once, or, in a second or so, it is gone. Such shooting demands a wide spread of shot at close quarters, both to increase the chance of hitting and to reduce the chance of mutilating. In trap shooting, on the other hand, and in wildfowling, it often is necessary to hit hard at a considerable distance, and this requires the close pattern given by a full choke.
The pattern tables commonly published in gun catalogues are not of much use in the field. They show nothing but estimated performances of various chokes, with all sizes of shot, at the one range of forty yards. Game is shot at all distances from fifteen to fifty yards, or upwards. One should know what his gun will do at all sporting ranges. So I think it worth while to print here the average patterns obtained by actual firing with some quarter choke, half choke, and full choke 12-gauge barrels, at five-yard intervals, from twenty-five to fifty yards, and with three different charges—standard duck, trap, and upland loads. The figures show the number of pellets within a thirty-inch circle at each range. At twenty yards, all of these chokes place the full charge inside a circle of that size.
3% drams bulk smokeless, 1^ oz. No. 6 chilled shot (279 pellets).
at 40 yds.
at 40 yds.
at 40 yds.
Drams bulk smokeless, \y± oz. No. ly2 chilled shot (431 pellets).
12-GAUGE PATTERNS OF
3 drams bulk smokeless, 1% oz. No. 8 chilled shot
Bear in mind that these figures are averages. Any gun will vary ten per cent between shots, and sometimes a good deal more, but the tables show what may fairly be expected in the long run. Other gauges, of same chokes, will make similar percentages at the various distances, with shot adapted to them. It will be observed that the smaller sizes of shot show a falling off, in pattern, at the longer ranges. This is because they lose momentum faster, and hence the pellets stagger and fly wild.