Part 17 (2/2)

The smaller pocket automatic pistols are lighter (the two-and-a-half pound ones are military pistols).

A pistol weighing under two and a half pounds can shoot only a small charge with light recoil, and so is easier to make.

The heavy recoil from a military rifle (which gives the bullet a speed of some thirty thousand feet a second) would shatter the recoil mechanism of a small pocket pistol, though the latter can quite safely operate under the slight recoil of its weak cartridge.

With a magazine rifle or revolver, the shooter uses just sufficient manual force to operate the mechanism, and even then pistols and rifles may get damaged by a clumsy man using too much force to wrench the weapon open or slam it shut.

If, instead of the intelligently applied strength of a man, using the minimum force necessary, you subst.i.tute the smas.h.i.+ng blow (several tons'

weight to the square inch) given by the force of gunpowder, to operate delicate mechanism, you can realize the difficulty the inventor has to contend with.

It is as if you have to invent a firearm which would operate if, after each shot, you threw it under a pa.s.sing railway train.

CHAPTER XXIII

THE MECHANISM OF THE AUTOMATIC PISTOL

What the maker of the automatic pistol has to do is to restrain the sudden smas.h.i.+ng blow of the explosion on his mechanism and have it operate gently. (See Plates 13 and 14.)

The safety of the shooter depends greatly on _the breech of the pistol not being opened till after the force of the explosion is spent_.

If the breech is opened before the force of the explosion is spent, it will drive the cartridge out like a bullet, and the pistol will in fact be shooting from both ends at the same time.

Now will be seen why a very light-charge rifle or pistol is easier to be made a practical automatic firearm.

With a very light charge, the explosive force is so light that, as long as it does not instantly blow the breech open (but r.e.t.a.r.ds it ever so slightly), there is no harm done.

Rifles and pistols have long been made to shoot light charges that do not need the breech securely locked during the discharge, and are perfectly safe to use.

The original automatic pistol operated as follows:

The discharge drives the mechanism back against a spring at the same time that it blows open the breech, which the recoil spring then closes, inserting a fresh cartridge. The spent cartridge is blown with some force sideways out of a slot at the side of the mechanism, so that it may not hit the shooter in the face.

In some makes of pistol, the cartridge is not blown out but merely dropped out.

With a suitable charge the breech-closing mechanism can be made heavy enough for its inertia to keep the breech closed sufficiently long after the discharge.

When it comes to such heavy charges that it is necessary to keep the breech closed till the force of the explosion is spent, the difficulty of making a safe automatic firearm begins.

With a military full-charge rifle this has hardly yet been arrived at, hence the delay in its being used for military purposes, but it seems as if the problem is on the point of being solved.

For the comparatively weak recoil of a pistol, this does not apply. There are several perfectly safe pistols in use, and there is no danger in using any of the well-known makes.

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