Chapter V: Triggers and Trigger Pull and the Single Trigger

The trigger of a gun might be said to be the means of communication between the brain of the marksman and the charge in his weapon. If the communication is faulty, the brain’s work is wasted. The brain would find it useless to give quick and sharp commands to a slow servant. The eye, the brain, the finger, the trigger, and the charge make a team in which, if one member balks, the efforts of the others are misspent. It follows that if everything else about a gun is right, including the man behind it, and the trigger pull is wrong the combination is no better than a steel chain with a wooden link.

The technical term trigger pull means the weight that must be attached to the trigger in order to release the sear from the hammer notch. In arms built to order the manufacturers are always willing to adjust the pull, within limits, to suit the wishes of the purchaser. On guns placed in stock the weight of pull is placed at what would please the average man or perhaps a trifle harder on the ground of safety.

The trigger pull on a shotgun for a normal man should be from three to five pounds. It should vary somewhat according to the temperament of the shooter, and the weight of the arm governs it in a minor degree. A man of quick action and nervous temperament will find it wise to have his pull adjusted a bit hard, and a heavy weapon that needs a strong grip to handle and swing requires a heavier weight of trigger pull than will a light piece. Field gunners, who shoot from all positions, sometimes twisting and cramping the shooting arm or straining the finger to reach the trigger, will need a pull from one-half to a pound heavier than the trapshot.

Trigger pulls may reasonably vary from three to five or even six pounds, but if the trigger is lighter than three pounds it may become a source of danger to others through a premature let-off as well as a fruitful cause of poor marksmanship. There are always moments of excitement in the field when the gunner is liable to discharge his piece without being in the least conscious of having pressed the trigger; especially is this true in the case of a novice where the trigger pull is too light. The greater the experience of the sportsman the more sensitive he becomes to the weight of his trigger, and in such hands the pull might well be adjusted to the minimum weight. The tyro must not pattern after the veteran, however, in this respect or he will find himself in trouble and everybody else that goes afield with him. It doesn’t matter how naturally sensitive the touch is either; I have known ladies with the most delicate hands to give a four pound yank on the trigger without even knowing it was there.

There are exceptions to all rules and this applies to the pull of triggers. A shooting companion of mine used a gun with a trigger pull of scant two pounds, and another pulled eight pounds on his first barrel and ten on the second--and he was a good shot too. Nevertheless, it would not do for the average man to follow the example of either of these.

Heavy trigger pulls, from five pounds up, are generally found on cheap guns. In these the hammer and sear are made of a soft quality of steel and it is needful that a deep notch be cut in the hammer to allow for wear. Such arms gradually change the pull-off with use until the hammer will no longer stand cocked.

Not only do the cheap and nasty weapons have a heavy pull but what is worse it varies, at one time yielding with a pressure of seven pounds and at another of five. It has been estimated that it requires a quick man to press his trigger in a hundredth part of a second after his brain has given the order, and if it doesn’t yield within a thirtieth of a second the result is a certain miss. This is scientifically explained on the ground that if a bird is flying sixty feet a second he will cover two feet in the thirtieth of a second and be entirely outside of the shot pattern. This is especially true of the snapshot who must get off at exactly the right instant or miss, while the swinging shot who carries his piece along with the bird might still have a chance of connecting.

The hard pull and the variable pull are bad enough, but the creeping or dragging pull is fatal in wing-shooting. In the drag pull the shooter presses the trigger and feels it yield, but the sear after partly releasing still maintains its hold on the hammer and a second pull is necessary--the trigger continues to creep and finally lets go unexpectedly. Skill and practice are all wasted with such a trigger, and the arm is only fit to shoot rabbits in their form or quail huddled on the ground.

Moreover a trigger should yield sharply if accurate work is to be accomplished. If the trigger moves a great distance in the let-off it will affect the grip of the hand and disarrange the aim, probably jerking the muzzle down. All of these features of a bad trigger pull contribute to those inexplicable misses that all of us have experienced.

Many prefer that the rear trigger should pull a trifle heavier, say half a pound, than the front trigger. This is for the reason that the back trigger is in the best position to be given a natural pressure with the grip of the hand, while the forward trigger strains the finger more and is not pulled in precisely the same direction.

The principles that govern trigger pull are: Too light a pull causes premature let-off and tends to shooting low and behind. Too heavy a pull means shooting ahead on a swinging shot and above in a snapshot. A pull with weight enough to impress the gunner as being _hard_ is fatal to regular time and accuracy. A creeping pull renders the arm worthless. It is better for the novice to err on the safe side by being sure that his pull is heavy enough; later it can be eased without trouble by any gunsmith. Do not expect a good trigger pull on a cheap arm.

THE SINGLE TRIGGER

A single trigger is a contrivance by which both barrels of a double gun are pulled by one trigger which is usually placed in the rear position. Mechanisms vary in the different models of one triggers, and any of them are too complicated to be accurately described without the use of diagrams and cuts or an actual inspection of the parts. It must suffice here to notice their principles briefly.

In the single trigger there is a slide or bridge which, when one trigger is pulled, moves across and engages the sear of the opposite lock permitting the gunner to let it off with a second pull. This movable bridge can be set by a slide so as to pull either barrel first at the will of the shooter. If it is intended to use the right barrel first, the bridge is set for right, and that barrel will go every time it is cocked, the slide only moving over to the left when the first hammer is down. Should the bridge be moved to the left sear it shoots that barrel first so long as permitted to remain in that position.

The advantages of the one trigger are that you can use heavy gloves without being balked by having two triggers in the way. The pulling is more uniform and the grip fits the hand better, for it is not to be disputed that the grip and direction of the pull for double triggers are not the same, and if one trigger suits the hand the other will not. Moreover, the balance and fit of the arm are not disturbed as they are in a two trigger gun where the grip must be released and shifted up or down for the right and left barrels. The shifting of the grip tends to alter the length of stock also as will be mentioned in gunfitting and measurements. The rear position for a trigger is the only correct one, moreover, since it gives a firmer grip, does not strain the hand, and enables the pressure to be applied in the most natural manner.

Other advantages are claimed for the one trigger, such as much greater rapidity in the use of the second barrel, even to the extent of getting onto a bird moving at the rate of sixty feet a second fifteen feet quicker with the second shot than with a two trigger gun. The experience of the author, who has used a single trigger gun three years steadily, does not bear this out, though it would appear a most reasonable claim to the inexperienced. Indeed, if a gain of fifteen feet were made over the double trigger the second barrel would have to go instantaneously, because a quick shot with two triggers, who continues his swing after the bird, can just about catch it again in fifteen feet or a quarter of a second.

My own conclusion is that the single trigger in the case of a heavily charged twelve bore gun is no quicker than the double triggers. The recoil of the arm is such that the muzzle is thrown well off the target despite the firmest holding, and while the gunner is getting on again he can readily shift from one trigger to the other.

Doubtless this claim of greater rapidity might be borne out if the mechanism were placed upon small bores with very light charges, for it is quite true that without loads in the barrels the two locks can be sprung much more rapidly with a single trigger than with two. In calculating the possibilities of rapid firing, recoil, the action of the shooter’s mind, and the need of a second aim must not be overlooked.

I have every faith in the single trigger, believing it a positive advantage and pleasure to use even in its present stage of development. Nevertheless the conviction is forced upon me that no single trigger now invented is perfect, neither will any of them quite bear out the claims of the manufacturer. The problems incident to the construction of such a trigger are complex and rendered more so by the difference in men and their style of shooting. I knew one man who nearly always let off two shots from his automatic when he intended to fire but one.

The theory on which the single trigger is made is this: When the first barrel is pulled the recoil of the weapon shakes loose the grip, the trigger springs forward, and the sliding bridge moves across to engage the second lock which can then be fired also. Now should some gunner occasionally have such a firm grip on the stock that the trigger could not spring forward, he will be balked when attempting the second shot. I have shot with one man who had this happen frequently, and that with a trigger which is advertised as being impossible to balk.

There is no one trigger that cannot be balked by some men, though in order to prevent this the inventor of one such action constructed a trigger that only needed to move forward the thirty-second of an inch to engage the second sear. It is obvious that carrying this scheme to a legitimate conclusion would mean a trigger that did not have to move forward at all to engage the second sear; then we would have an action that would really be impossible to balk. But it could double discharge with the greatest ease and certainty, and it would. Even with the trigger springing forward a short distance doubles may occur from the rebound of the piece after it strikes the shoulder.

Doubles are worse than being balked, too, as any one will admit who will try the experiment of firing six drams of powder and two and a half ounces of shot from a seven pound gun. For this reason I should prefer a trigger that returned quite to its original position before engaging with the second sear.

It must not be concluded that doubles and balking with one triggers are a common occurrence, for with some men they never happen and with others rarely, but the point that I wish to make is that they are not impossible, and any advertisement so stating is misleading. It has been estimated that in doubles with a single trigger the second shot may follow the first in one-fiftieth of a second, practically both barrels going off as one so that only one report is heard. How this can happen with such rapidity the writer can only conjecture unless the movable bridge in springing across touches and springs the sensitive sear of the opposite lock. I am not trying to indict the single trigger, but only pointing out the mechanical difficulties of making it perfect.

The one trigger has other defects which I think can readily be remedied. One of these relates to the instantaneous choice of barrels. The builders declare that a choice of barrels can be made instantly, that is with the same quickness that a man would take his finger from the front trigger of his open barrel and place it on the trigger of his choked barrel when a bird sprang up at long range.

This means that the change would have to be made as the butt slammed to the shoulder and without interfering with that motion. This could be done provided the change could be made mechanically as in pushing up the safety slide on top of the tang, the time required not being more than one-fifth of a second. However, such one triggers as we now have shift with a tiny button under the frame where it is hard to move and difficult to get at, necessitating the gunner’s taking his eye and mind off the game and then requiring at least ten seconds to make the change. Imagine where a swift-flying bird would be that got up at long range and was given a handicap of ten seconds.

There are three positions where the shift might be worked with sufficient rapidity, one, the present position of the safety slide on top of the tang where it could be moved by the thumb as the piece came up, second, in the position of the Greener safety, and, third, in the shape of a trigger just inside the front end of the guard where it could be moved forward by the back of the forefinger as the gun came up.

The author is having a single trigger gun built in which the ordinary trigger safety bolt has been omitted and replaced with a selective slide that will change barrels as quickly as you could shove up the safety on an ordinary hammerless gun. With the present models of one triggers there can be no selection except from deliberate calculation as to what kind of shot you are to expect next.

The single trigger sometimes causes the loss of a shot, too, in this way: The first barrel has been fired scoring a kill, and as usual the sportsman at once breaks his gun to replace the empty shell. When he has withdrawn or ejected the empty shell and before he can replace it with a load, another bird breaks out. With a two trigger gun the hunter would at once snap down the barrels and fire the one that was still filled, but should he attempt this with a single trigger the first lock will go again with a useless click and the opportunity is gone. Doubtless long use of the single trigger would cause the sportsman to make the first futile pull as his piece came up, but most men are accustomed to the discharge of the arm when the trigger is pulled and their first thought is that the shell has missed fire.

Despite the minor drawbacks enumerated and the opinion that no single trigger now in use is perfect or past improving, I should, nevertheless, much prefer it to a double trigger and would not willingly go back to the latter. The one trigger is following in the footsteps of the hammerless action, the self-ejector, and other improvements that in the nature of things are bound to come. Meantime we can await with confidence the American single trigger that will finally replace all the others.