A small fraction of this gas rushes through the hole into the tube and operates the mechanism.
This has been the principle I have always worked on in trying to solve the problem of an automatic firearm.
One system uses the recoil, tempered by a buffer, to modify its force.
The other consists in diverting enough gas from the big explosion to operate the mechanism gently.
It is conceivable that by this latter system it would be possible to convert the explosion of a siege cannon into a force just strong enough to break an egg, and that by two such divisions of the explosion, one would open the breech and the other close it, without the necessity of any anti-recoil mechanism at all on the principle of the slide valve of a locomotive steam engine. (My grandfather, Ross Winans, invented the locomotive slide valve, not Stevenson.)
I think I am right in saying that this system has not yet been applied to automatic pistols, and that they all operate on the recoil, driven back by a compressed spring.
A fault in every automatic pistol I have yet seen, is the difficulty of first loading it.
The cartridges are carried in a clip, which is inserted in the butt of the pistol and drops out on pressing a button. Most automatic pistols indicate when this magazine is empty and the pistol unloaded.
This is very good, but what I complain of is that, after the magazine is full, you have to bring the first cartridge into the barrel by hand, after the first shot the cartridges are fed into the barrel and the empty ones ejected, automatically.
When getting the first cartridge ready to fire in a revolver you accomplish it in cocking the pistol, and with a magazine rifle by working a bolt or lever.