Pugs, I recently bought My first Cooper mod 57 Classic, I like the rifle but about half the time it wont feed the last round out of the mag no matter what ammo I use, (it jams)exactly what did you tweak on your magazine?
Indeed I was a bit surprised at the malfunction too but I called them and ask if I should mail it back. They said they would be happy to fix it but he suggested before I went to that trouble I simply bent the lip in a tiny little bit on each side of the very front of the magazine. I did so a very little bit, you could hardly tell I did it, and it worked fine with the Super X conicals I like.
I do need to get another magazine for silhouette season and I'll be curious if that one needs tweaked too.