Firearms cartridges

[johnreed]

Guy, there is one Artilley equipment which has a smooth bore and that is the MRLS. With regards to using brass for cartridge cases, you will find that the brass which is used is soft brass as opposed to hard brass, hard brass has completely different properties and is very brittle. Soft brass is very malleable hence being able to be recycled. It also expands under heat rapidly therefore a great method of obturation especially with pressures of about 20 tons per sq in. in the chamber and contracts rapidly i.e. ease of extraction. A 1cm cube of cordite produces about 1400 cubic cms of gas and in burning cordite produces its own oxygen.

John

[NIGEL]

The advantages of a smooth bore gun against a rifled barrel is that you can obtain much higher volacities with a smooth bore barrel. There is no leakage of gases between the rifling and also a rifled barrel can only obtain a certain volacity before the bullet will start to shred on the rifling in the barrel. A smooth bore gun can obtain virtually unlimited volacities as the cartridge which is holding the projectile is pushed against the barrel of the gun thus giving a gas tight seal all the way up the barrel.

When the projectile hits the air the fins on the projectile will make it spin at the right speed to suit the everdecreasing speed of the projectile so it will always be accurate. Whereas, a rifled barrel bullet starts to lose its spin as soon as it leaves the barrel so the longer the range of the bullet/projectile the less accurate it is inclined to be. In the late 1960's when a camera of massive speed was invented and actually filmed a shell in flight, it was found that towards the end of its flight (range) the shell was actually wobbling in flight, this was due to the spin of the shell being incorrect for the actual speed of the shell at the end of its flight.

Also in a smooth bore gun a range of ammunition guided and unguided can be used, whereas it is difficult to do in a rifled barrel artillery piece because of the method of propulsion. The method of propulsion in standard artillery piece rifle is a controlled burn takes place in the breech of the gun which pushes the shell/bullet up the barrel. In a smooth bore gun (Iraqi Super Gun) the controlled burn can take place all the way up the length of the barrel as the gases expand, so that there is not the initial shock taking place as in the breech of the gun. This technology is years old and works on the principle similar to a shot gun.

One of the problems of all artillery pieces now being smooth bore is that all the ammunition will have to be completely changed to suit the new method of firing. Also as John Reed has said cordite produces its own oxygen when it burns all propelents, in fact anything that burns needs oxygen for this process to take place. So that is why modern day propelent powders are used so the amount of oxygen released can be controlled during the burn, and it is basically the hot gases which do the business instead of an explosion or fast burn as you get with black powder etc.

I would go on, but before i was shouted down, and it can get really boring unless you are interested----------so sleep tight zzzzzzzzzzz!!!!!!!!!!