Or more specifically, why don't they burst? You have huge pressures behind them, they're thin and not really solidly fixed in place, and yet they are expected to stay intact - how?
Me and colli were discussing this on TS yesterday, and there's no way inertia of the firing pin could be providing meaningful support - from squinting at a pressure Vs time graph of a 30.06, and assuming the firing pin can be modelled as a piston of radius ~1mm acted on by the chamber pressure, the applied impulse is on the order of kgms-1. So that firing in should be moving backwards at a considerable velocity, given the light weight, and over the ~1millisecond of the firing process it should move several mm back - yet primers retain the impression of the firing pin after firing. The peak force applied was on the order of kN, so I'd be very surprised if the firing pin spring was providing enough of a force to resist this
pic from TankNet.
I feel uncertain whether its cannon's caliber was 140mm or not, I found a figure at the document AD-A228 389 showed behind, which label the gun as LW 120.But in many ways I've found its data in websites all considered to be 140mm.
AFAIK,the first xm291(140)demonstrator was based on xm1 tank, and the successor was the''Thumper'' which was fitted with a new turret look like the CATTB but still m1a1 hull(Maybe it was CATTB's predecessor? )
I will really appreciate if anyone have valuable information to share
Anti-air bobcat design to take away driver's hearing in maximum efficiency
SH11 155mm SPG