Chapter III: The Frame

The frame of a gun is that part to which the barrels are jointed at one end and the stock attached to the other. The frame, together with the mechanism which it contains, is mechanically the most important feature of a double hammerless shotgun. The life of a shotgun, its strength and continued soundness, are directly dependent upon the bolting mechanism, while the locks must be of such temper and quality as to fire thousands and thousands of shots without weakening.

The frame itself is made of a solid block of drop forged steel which is then milled out to contain the working parts, filed into shape, polished, and case hardened when finished. There are at the present time two types of frames in common use, the box-lock and the sideplate. These will be treated more fully under the heading of locks. I have never known the frame of a shotgun to break down, and it need only be said of them here that they should be as light as possible consistent with strength. A heavy frame is a great handicap to a gunbuilder who is trying to maintain the correct balance of his weapons in all weights, since a heavy frame and a light, short barrel are sure to result in a butt heavy arm.

LOCKING BOLTS AND FASTENINGS

In the first models of breechloaders made the barrels were locked down on the frame by a bolt actuated by a lever under the fore-end. The lever swung out to drop the barrels and this model of gun was known as the Lefeucheux, a French invention. Then the English improved upon this by swinging the lever about under the guard and giving it double bites or bolts into the lug. Subsequently the bolt was placed under the standing breech and was withdrawn by a side lever. Some of the early American arms were made with this side lever. All of these models of shotguns are now obsolete and need not be dwelt upon here.

The top lever now came into use of practically the same shape as those we now have. When the top lever was invented there was but one bolt which engaged with a lug under the barrels and was withdrawn to the rear. By and by this bolt was made to lock into two lugs in place of one and the arm was said to be double bolted.

Use and wear soon betrayed the weakness of these underbolted guns. The construction of the bolts was such that they could serve but one purpose, that of binding the barrels down to the frame, but as at least half of the strain in shooting is in the direction of driving the barrels away from the standing breech, there was nothing to withstand this except the joint which wore rapidly and the gun became loose. To guard against this the rib of the gun was finally extended to dovetail into the breech and was known as the

EXTENDED RIB

The original extension rib was termed the doll’s-head from its shape. It proved a great reinforcement of the simple underbolts, effectually preventing the barrels from springing away from the breech so long as the lug bolts did not wear and permit the rib to rise in its socket, giving it a play that allowed the arm to become shaky eventually. I have known guns fastened in this way to rattle after two years of service. But others remained tight and sound a good ten years. It is much a matter of quality of steel and the strain to which it is subjected. However, just as surely as steel grinding on steel will wear eventually, so will guns shoot loose that are simply fastened by lug bolts and a doll’s-head extension rib.

Inventive genius was not content, and a tapered or wedge bolt was placed in the rear of this extension rib to prevent it from rising. Many guns are still constructed with this style of fastening, especially those built in England and on the Continent. A further improvement, for such it undoubtedly was, placed a cross-bolt entirely through the rib, engaging with the frame on either side. This is the famous Greener cross-bolt much liked in Europe and adopted in this country by the Remington people for their highest grade of guns. It is a very efficient bolt, yet not beyond criticism. It is claimed that owing to the long bearing of this bolt in the frame considerable friction is entailed. This would not matter unless sand or rust gets into the action when the bolt may stick and require the services of a gunsmith to open the piece. In justice it should be said that such a contingency happens very seldom, and the cross-bolted gun should give general satisfaction.

The latest European addition to the lug bolts and the Greener cross-bolt is the Purdey side-clips, a projection of the frame to cover the ends of the barrels, designed to prevent all lateral action. The side-clips have never been used on an American arm, neither are they very highly regarded over here, the bearing of the lugs in the frame and the deep extension rib being quite as well adapted to withstanding lateral strain. The celebrated Continental, quintuple fastening as found on the Daly, Francotte, Cashmore, Sauer and other guns, consists of Purdey side-clips and Greener cross-bolt, with shoulder bearings to the extended rib and double underbolts.

THE ROTARY BOLT

It remained for America to have the final word in bolting mechanisms. Our clever mechanics early discovered that the lug bolts were in the wrong position mechanically. The joint of the barrels acts as the fulcrum of a lever upon which the barrels rest and pry at the bolts. It is easy to understand, therefore, that the closer these bolts are to the joint the more leverage the barrels have and the stronger the bolts must be. It takes three times as much strength in bolts to withstand the pressure if they are placed an inch from the joint as it would should the fastenings be three inches away. This and other considerations led American builders to take their locking bolts from the lugs and place them in the extension rib which is undoubtedly the right position for them mechanically.

Our manufacturers also wisely concluded that one bolt or fastening in the rib was enough _provided_ it could be given such strength and bearing as never to shoot loose. This fastening was at last found in the heavy Smith rotary bolt. This tapered bolt rotates and is driven through a square opening in the rib with the full strength of a heavy spring. As the bearings wear, this spring automatically drives the bolt farther in. It is the only locking mechanism in the world that is guaranteed never to loosen with use, lack of use, or misuse. Experience bears out this claim and the writer has no hesitation in saying that throughout the world no other locking device should be used on a shotgun save the rotary bolt. It is now in use on the Smith, Fox, Stevens, Baker, and other guns while the Ithaca has adopted the same principle in a slightly different form.

I am persuaded from the experiments of myself and others that no great strain is put upon the locking bolts of a shotgun by firing it with ordinary charges. Taking away all bolts and simply fitting the arm with a doll’s-head extension rib, it has been discharged while merely holding the barrels in place with the hand. The barrels have also been tied down with a thread which remained unbroken when the piece was fired.

It is not so much the strain of discharge that finally loosens a gun as its constant manipulation, the opening and shutting, the prying weight of the barrels against the bolts when the weapon is being carried and jostled, the dropping down of the barrels with too much force. The steady grinding of steel on steel must wear in course of time whatever the hardness or quality of the metal, and provision should always be made for taking this up mechanically. The rotary bolt does this automatically and with absolute certainty. An English gunsmith said when examining a rotary bolted gun that had been in use some years: “Why, the piece _is_ loose but you can’t tell it because of the bolt, you know.” The rotary bolt is a good thing for the owner of a gun but is not calculated to throw much repair business into the hands of a gunsmith.

THE BOX-LOCK AND SIDEPLATE LOCK

American shotguns are made with either box or sideplate locks. The latter is very much the same as the old hammer lock except that the striker is placed inside instead of out, and provision must be made for the barrels raising the hammers in place of by hand. Indeed this lock is a survival of muzzle-loading days and, though simplified and improved, is not essentially different from those used on the flintlock.

Many believe that the sideplate gives the arm a better and more racy appearance. This can be judged from the engravings of the two styles of frames. Certainly the plate gives the engraver more latitude, and he has no ugly and square lines to deal with. It also permits a lighter frame which is an advantage.

On the other hand, the box-lock admirers contend that the plate lacks both the strength and the easy, certain manipulation of the box. This is for the reason that part of the pieces constituting the plate lock are contained in the plate while others are fastened to the frame. Should the gun become wrenched or the wood swell from exposure to the weather the pieces may not come together accurately, thus leading to jar-offs or other trouble. A few go so far as to contend that every plate lock should be fitted with an extra tumbler safety in order to guard against the probable jar-off. I believe myself that a better cheap gun can be made with a box-lock than with plate, but where the weapon is carefully constructed I have never known any trouble to occur of any kind, neither would I give the matter of a box or plate lock a great deal of consideration when purchasing a gun of a reliable maker.

Certainly the plate lock has one decided advantage in that it can be taken off for examination, cleaning, or repairs very readily, while the other form must be taken to a gunsmith. This has been given so much consideration by the gunmakers that one of them has invented a hand-detachable lock for his box-frames. However, good general advice to the amateur is to let his locks alone so long as they are attending to business. More locks have been injured by the novice tinkering with them than have ever been hurt by wear or weather.

When the embryo gunsmith feels like experimenting with his gun locks he had best buy a cheap arm for that especial purpose. It may not be any more worthless when he gets through than it was before, but he will probably find himself in the position of the tinker who took an old fashioned clock to pieces and never again could find room for all the parts. He said it looked just as well as ever when he got it together and would have run except that it refused to tick.

In passing, one advantage of the box-lock should be noted. It can be and generally is used with a coil mainspring in place of the flat. These coil springs are guaranteed to last forever, while such guarantee could hardly be given with a flat spring, or at least never has been so far as the writer can recall. One English gunmaker who uses flat springs recommends that an extra pair of locks be purchased with every gun (at an extra cost of fifty dollars) so that if one should break another will be at hand. To many it might appear good sense to buy an unbreakable lock in the first place. The ability to use coil springs may ultimately predispose people to the exclusive use of a box-lock. Nevertheless, in fairness, it should be said that the majority of well finished guns are shot a lifetime without the breakage of a spring.

COCKING DEVICES

The hammerless gun is essentially an arm that cocks by some device through which the barrels in opening lift the hammers. One of the earliest and best of cocking mechanisms was that of Anson & Deely. It is still in use on some American arms and many of those made in Europe. In this mechanism levers are pivoted in the front end of the frame with one end projecting into the fore-end and the other resting under the toe of the hammer. As the barrels turn on their joint in opening the forward end of the lever is depressed while the other rises, carrying the hammer to cock, the whole action being performed very smoothly and reliably. This cocking system has been criticized as being generally used with a short frame in order to obtain greater leverage.

One of our American arms has a modification of the Anson & Deely cocking levers. This is a rod running straight through the frame from fore-end to hammer. This rod is fitted with a crank at either end, so adjusted that while one of the cranks is carried down by turning barrels the other rises, pushing the hammer to cock. The gun works without undue force and the parts are unbreakable.

THE COCKING HOOK

A number of our guns use a peculiarly American invention in the shape of a cocking hook. This has variations in the different makes of arms. The Baker raises the hammers by means of a bent arm which is pivoted under the standing breech. One end of this arm hooks to the barrels and the other has a crosspiece which thrusts directly against the hammers, pushing them back until caught by the sears. The Parker has a hook which actuates a slide, pulling the hammers to cock. The work is accomplished with as little friction as in any American arm.

The most modern cocking device, the simplest and what appears to be mechanically the best, consists of connecting the toe of the hammer directly with the lug of the barrel. The hammer is thus its own lever, and as the toe rises the striker drops back until caught by the sear. No lost motion is possible and very little friction is entailed. At present it is hard to see wherein this device can be improved. The Fox and Ithaca guns are lug-cockers.

SAFETY BOLTS--TUMBLER BOLTS

When hammerless guns appeared the old guard of conservative veterans naturally set up a roar. Here was a muley gun that was not only at full cock when game was afoot but remained so every blessed minute of the time you were afield. It was regarded as certainly a dangerous weapon, likely to kill somebody at any time. No matter how careful the gunner might be about accidentally pulling his triggers, there was nothing to prevent a jar-off such as had happened with hammer guns more than once. The assurance of the makers that jar-offs were practically impossible and that the arm was really safer than the piece with outside hammers did not silence the outcry, and only years of use, fully bearing out the claims of the manufacturers, at last ended it.

The absolute safety of the hammerless gun was secured by means of two bolts, the safety or trigger bolt and the hammer or tumbler bolt. The first only was necessary as proved by experience, but the latter was needed to silence the kickers.

The safety bolt is pivoted in the frame in a perpendicular position; the upper end of this lever is attached to a slide on top of the tang, just behind the top lever; the lower end comes snug against the triggers, absolutely preventing them from moving while the bolt covers them. In order to permit the triggers to be pulled the top end of this bolt, connected with the slide, must be pushed forward, throwing the other end back off the triggers. This bolt, so adjusted, is known as the non-automatic safety for the reason that it only bolts the triggers when the slide is moved by hand.

In order to make the trigger bolt automatically assume its position over the triggers, a piece was fixed in the frame extending from the safety bolt to the post of the top lever. Every time the top lever was turned in opening the arm this bar mechanically shoved the safety bolt over the triggers. This is called an automatic safety.

The tumbler safety is a bar that rises directly between the strikers and the firing pins. This bar is actuated by the triggers; and, unless these are actually pulled, it retains its position preventing the hammers from striking the firing pins. It will thus be seen that should the hammer be accidentally jarred off the tumbler safety would catch it and there could be no accidental discharge. It would appear that no further safety devices could possibly be necessary on a gun than the automatic trigger bolt and the automatic tumbler bolt.

However, many regard the tumbler safety as really a bit of useless machinery. It has been demonstrated that with honestly made locks the hammers absolutely cannot jar-off while the bolt is on the trigger. Experiments have been made of the most radical nature to prove this. With triggers that pull at the ordinary weight, the arm has been dropped on a stone floor repeatedly from an increasing height until the stock was smashed, and yet the hammers refused to jar-off. It has been proved that jar-off when it does occur, as in a gun whose trigger pull is set too light, comes from the movement and play of the trigger against the sear. Triggers are necessarily so fixed as to move easily, and a heavy jar like dropping the gun gives even such a light piece of iron as the trigger some momentum which acts against the sear the same as the pull with the finger. Moreover this play and force of momentum cannot act if the triggers are solidly bolted, though it might were there merely a tumbler safety controlled by the movement of the trigger.

Granted the foregoing is true, if the trigger can actually move the tumbler bolt out of the way in the case of a jar, then the tumbler safety is a useless encumbrance, only put there in deference to prejudice or ignorance.

In addition, it is argued that if the trigger is set to pull at three pounds, one-half of the weight will be used to release the sear from the hammer and the other pound and a half to move the tumbler safety out of the way, hence the gun is no safer against a jar-off with a trigger pull of three pounds and a tumbler safety than it would be with a pound and a half pull, exerted entirely against the sear. There is some truth in this, no doubt, for some of the force of the trigger pull must be exerted in moving the tumbler bolt out of the way, and this detracts just that much from the strength with which the sear engages the hammer.

Personally I have never been partial to the automatic safety, preferring that my gun should only be safe when I set it so. In a hot corner, when birds are rising in every direction, I wish to shoot without the trouble of shoving up the safety every time the arm is reloaded. I never yet knew a man with an automatic safety who did not lose occasional shots from forgetting to shove it up.

Nevertheless, I believe that where it is to be handled by a novice the piece had better bolt automatically. Should the bolt cause him to lose occasional shots he will yet be the gainer through the increased security of himself and companions. Besides should the gun have a very light pull-off it might be wise to have the triggers invariably bolted while the shells are being placed in the chambers and the barrels snapped down perhaps with great force. With the non-automatic safety the triggers are rarely bolted while the arm is being reloaded.

Individuals differ and what might be wise for one would not be safe for another. For myself I have never yet had a gun jar-off either when being loaded or at any other time except when the trigger pull was set too light and the recoil of one barrel jarred off the lock of the other. No kind of safety could guard against this.