I have an AB-10 that I purchased about a decade or more ago. I tried to shoot it one, but it wouldn't go bang. Recently I got it back out to see if I could get it running. It had a broken firing pin, but I replaced it. Now when I try to shoot it, it won't feed any cartridges in to the chamber other than the first one that I manually cycle in there. The cartridges end up pointing all sorts of way and getting smashed by the bolt. I'm thinking that the magazine is the likely problem. So, I'd like to try another. Obviously I don't want to spend too much on a magazine, but reliability is most important. What are my options? I've found:

There's obviously a big difference between $20 and $50, but does that represent a true reliability difference? Are there other options? I need to get this pistol running reliably to make the gun grabbers sad.