This defect of the cannon also applied to the use of the hand gun. Its range was small and consequently the blunderbuss type was invented to spread the charge of shot as much as possible so as to tear a wide gap in the enemy’s line and prevent it from closing in upon the operator of the gun. But the loading and firing of these early firearms was extremely slow and the battle-ax and even the arrow and the crossbow were much more effective weapons. So unreliable were the muskets of our Revolutionary War that in battle more dependence was placed upon the bayonet than the firearm.
THE SPINNING BULLET
Three important improvements were necessary to make the small gun a really effective weapon. First was the invention of a reliable means of igniting the powder; second the rifling of the barrel so that the bullet would not tumble but would hold a true course, and finally the invention of a cartridge and a rifle that could be loaded from the breech. These improvements were not completely effected until the time of the Civil War. Since then there have been further marked improvements: The power of cartridges has been increased; the bullets have been given a stream-line form so as to increase the range of the rifle and its power of penetration; the rifle has been equipped with a magazine for carrying a number of cartridges; and a simple mechanism has been provided for discharging empty shells and inserting fresh cartridges in a minimum of time.
Gyroscopic action plays a very important part in the flight of a bullet or shell. The spiral grooves cut in the bore of the rifle give the projectile a twist that sets it to spinning rapidly. The spinning bullet is virtually a gyroscope and maintains its axis in the line of flight. Hence it is possible to use a long pointed bullet instead of the round ball of earlier days and to give the projectile a shape that will enable it to cut through the air with comparatively little resistance. The same bullet fired from a smooth bore gun would begin to tumble and would encounter so much air resistance that it would fall short in the space of a few hundred feet, besides which it would wander far off its course.
MACHINE GUNS
A rifle is really a machine for hurling small projectiles. During the Civil War a Chicago physician named Gatling fell to pondering over the inefficiency of using a machine that would fire only one bullet at a time with a considerable interval of time between shots for reloading, and he hit upon the idea of developing a machine that would discharge a continuous stream of bullets. So he built a ten-barrel revolving gun operated by a hand crank. The barrels were automatically loaded and fired one after the other. Although it was slow to accept the Gatling machine gun, the U. S. Army after once accepting it was loath to give it up even after better machine guns were invented.
UTILIZING THE KICK OF A GUN
In the Gatling gun hand power was required to operate the loading, firing and shell-ejecting mechanism, but it occurred to another inventor that a small portion of the energy developed in exploding the cartridge could very well be utilized to replace the hand power and thus make the machine gun completely automatic. It was Hiram Maxim who first carried out this idea to a successful conclusion. When a rifle is fired the suddenly expanding gases push back against the breech of the gun with just as much pressure as they do against the bullet and this shows itself in the recoil or “kick” of the gun. Maxim utilized the kick of the gun to cock the gun, open the breech, eject the empty shell, take a fresh cartridge out of a magazine belt, insert it in the breech chamber, lock the breech and fire the gun. All these operations occupied but an instant of time and the gun kept on firing as long as the belt of cartridges held out.
John M. Browning, inventor of the Colt gun, instead of using the recoil, employed a small portion of the gases to operate the mechanism. A minute hole in the barrel of the gun, near the muzzle, communicated with a small cylinder in which was a spring-pressed piston. The gases pursuing the bullet out of the barrel would find this tiny hole and, entering it, push back the piston. The pressure against the piston would be only a small fraction of that exerted against the bullet and would last for only the briefest part of a second, from the time the bullet uncovered the hole to the time it emerged from the barrel and liberated the gases, but this minute portion of the energy of the powder was sufficient to actuate the mechanism which performed all the operations necessary to reload and fire the gun.