Ballistics

[pmccarthy]

When I was about twelve years old, a friend and I were playing with a revolver. I think it was a .32 caliber. We made a cardboard target in the shape of a man, and found that if we aimed at the knees we could hit it in the chest. Our theory was that the recoil had thrown the gun up before the bullet left the barrel. Is that likely?

[old man emu]

Exactly. The reaction tube (barrel) is above the axle of the lever system (wrist) so that when the barrel moves backwards in response to the forward movement of the gas and projectile, you have a short "lever" between the centreline of the barrel and the centreline of the pin through the wrist. The combination of the force and distance produces torque, which is the force that rotates the pistol around the wrist. Because of teh way we hold a pistol, the direction of least resistance for that turning motion is up and around. That is why, with any firearm, you try to pull the barrel downwards by holding it tight to stop that upward movement.

 

At the same time, the pressure your finger exerts on the trigger also produces torque. It is to the right for a right-handed shooter and vice versa for the left handed. You can tell if your grip is not strong enough if your hits are high and to your trigger hand side.

[onetrack]

The length of a barrel largely determines bullet accuracy. Revolvers, pistols and any other short-barrelled firearm are notorious for accuracy, they're close-quarter, short-distance (20M) weapons.

I can clearly recall when we were going through the Jungle Training Course at Canungra in 1970, the Sgt gave us the Australian military 9mm pistol (a copy of the Browning 9mm), and threw his bush "giggle" hat on the ground about 20M away, and asked us to hit it with the pistol.

Of course, we thought we were all top class shots who could easily drill a hole in the centre of the hat with ease - but not one of us could even get a hit within half a metre of the hat! It was quite a reality check, after using SLR's.

The only place the 9mm pistol was handy, was when you had to clear out VC/NVA tunnels, and you might have a sudden close-quarter contact.