With the stock upper that comes with it, it runs like a clock, but I would like to be able to run other uppers on this gun and it just does not appear that I will be able to do so. I think this may also be a similar issue to a long barrel upper and my M10/9 that I never resolved and simply sold off the upper! I noticed after the gun would fire 3 to 5 rounds then stop and Fail to fire (with light primer strike) that the bolt had been dragging across the feed lips of the magazine. I think mag catch adjustment may be necessary.but before I go cutting and grinding on tings, I'd like to see some additional info. Once it feeds the first round it runs like a clock, but I have to release the bolt many times to get the first round to feed. I am working with an M10/45 with a Lage upper and it appears that the bolt is dragging across the top of the magazine and slowing things down. I am really, really sorry to reanimate an old thread, but is there somewhere I can get additional information on magazine catch and feeding issues as noted in the quote above? The reason the mags are not feeding may be because your mag catch is not adjusted right it may need to be cut to fit the mags. Yep, same ones you can buy for $9.00 now. During the 1994 ban I paid $104.00 for a 32-round 9mm UZI mag, I can remember the dealer telling me 'you will never see these again'. Of course like stocks these type 'investments' can go down in value. I doubt if I will keep them the rest of my life and will someday sell them, so in effect I'm leasing them. Thanks for the link.ДЄlthough they are expensive I think of things like the mags as sort of an investment. Web site has them at $66 for 2Д«etter link #3 on the page! I didn't use the word cheap, I know they are not.if originals work they are worth it to me. Got a couple 32rd double feed mags from and played with them a bit. I had a chance to buy 5 of them last year for $550. Sometimes you can find some for $100-$150 each. Cheap Original 9mm MAC10 mags- Hmmmm I hear the tooth fairy bought them all up and will give you one if your a good boy!

Mac 10 9mm 10 round mag stop