That is a lot. At that kind of pressure, canned goods, most sealed containers, even some hydraulic systems would be crushed.
Odd ball APS question: would an ordinary cartridge, say a 30-06, be crushed or would the water push past the neck?
I suspect whether the water seeps in depends on how fast the pressure is built up, that is how fast the ship goes down.
But neglecting that,
in general, thinner walls of a vessel are required to contain pressure than to resist outside pressure.
If there's inside pressure, the walls are subject to tensile stress which gets distributed. But if there's any fault in the wall of a vessel resisting outside pressure, the stresses are concentrated at the fault and catastrophic failure occurs. (That's why vacuum packed canned products have ribbed walls --to strengthen them.)
I suspect as pressure builds up on a cartridge, ultimately the bullet would be forced into the case before the walls collapse.
I always used an inertia bullet puller, so I don't know what force is required to pull a bullet* (without the case neck expanding from burning powder pressure), but if someone knows the force to pull a bullet, it would be the same force (approximately) to force the bullet back into the case.
The fluid pressure required to estimate** this is easily calculable, since force equals pressure times area, and we know the frontal area of the bullet. E.g. a .308 bullet has a frontal area of 0.0745 square inches if my arithmetic is correct. ETA at that depth, that would be 580 pounds of force pushing the bullet back in the case. Assuming the case didn't collapse before it got that deep.
Terry, 230RN
*Or to seat a bullet, offhand.
** "Estimated," that is, neglecting other variables, such as the clamping force on the neck due to the outside pressure.
