My brother and I went to the range with his new Chiappa 9mm M1 yeterday. Many FTFs with reloads, Winchester and Remmington ammo 115, 124, and 147 grain bullets and COALs of 1.1 to 1.16 inches. We were using the Pro Mag that came with the gun. We went into the store and asked for a Beretta mag which they had. I asked for a dial caliper and measured the width of the feed lips at the top of the mag and the Pro Mag was 0.15" narrower and you could see that it pinched the round tightly on its way to the chamber. Also the first round was always a FTF.
I took the Pro Mag apart and cut one coil off the spring and I opened up the feed lips to the Beretta spec - meatball surgery agreed. Then we loaded up the mag with 10 rounds and had one FTF. Tweaked the mag one more time by opening up the front of the feed lips a bit more and we ripped through 10 round mags flawlessly. Several mags that is.
We went back to my shop and pulled the mags apart and I showed my brother how poorly the Pro Mag is made, the feed lips have a heavy burr on the inside, you could cut yourself on the burr. This burr is digging into the brass casing and holding it up. We use rifflers to remove the burrs and then polished the feed lips carefully. The Beretta was much better but still improved with a bit of fettling and spring coil removal.
Now the gun runs beautifully through 10 rounds as fast as you can pull the trigger. Perhaps this will help others. It is a nice gun!
$85.00 for a Beretta magazine - gag, choke!