The Stant 10625 works on my M3A1. But as other have mentioned, it is a vented gas cap. It's possible to take it apart by uncrimping the outer shell and drilling out the assembly rivet. I used hi-temp epoxy to fill the vents. After which I reassembled the components and re-crimped the outer shell. After all of that work, I found that John Bizal at Midwest Military had a NOS cap, which I bought. So, unfortunately, I don't really know if the modified cap will work long term. Also, since it's a vented gas cap, I couldn't find any information on the release pressure.
