[PapaBear3625]

One thing that might concern me is that the cartridge case, besides containing gunpowder, also contains a little bit of air. Depending on how much air was in the cartridge, and how firmly the bullet was seated, decompression might result in the bullet partially or completely popping out of the cartridge case, causing a jam in the mechanism.

I decided to do the math before posting: a .38 bullet has a base area of 0.108 square inches. Atmospheric pressure inside the case would be 14.7psi, so the bullet would experience 1.6 pounds of unseating pressure, which shouldn't be an issue with factory rounds.

[BigpapaBo]

Room temp or vacuum of space temp?

[TXnMA]

You forgot temperature.

P=(NrT)/V