Re: Gas Checks
Well i cant say im speaking from experience, but i will say the following;
1. Aluminium has a much lower hardness than copper, copper is brinell 874Mpa whereas Aluminium is 245Mpa. The hardness of a material is directly related to its ability to be scratched or worn by other materials in contact with it. Therefore, aluminium would allow for considerably longer barrel life (in theory)
2. Aluminium has a shear modulus of 26Gpa whereas copper is 48Gpa. Therefore the ability of the gas checks to remain intact and not fail is reduced, therefore the gas checks would have to be thicker in order to withstand the same force. Not twice as thick as the strength of a material is propotional to the thickness squared. So you would need about 1.5times thicker in aluminium to ahcieve the same gas seal strength and resistance to stripping in the rifling.
3. If your considering using aluminium in projectiles, you would also have to consider the melting point vs heat generated from friction and propellant. Aluminium may not withstand the heat but it would depend on the caliber, speed, barrel length etc... AL would probably be fine in a pistol application where velocity is low, but from a high powered rifle it most likely would cause some melting of the gas checks where there is highest pressure and friction in contact with the lands... the seal may leak (maybe?). Whether this would be significant or inconsequential, i dont know...
How about some more info on what your doing?
Last edited by groper; 11-04-2010 at 08:01 AM.