I have a Rock River 9mm carbine that keeps on dropping the magazines while shooting.The magazines don't seem to matter Colt or Uzi.It appears as though the cartridges hit the magazine catch inside the mag well on their way up the magazine.That is the only thing I can think of.The magazines are seated in firmly and in all the way.I am looking for ideas on how to correct this problem.Thanks in advance

I had this problem.  In my case I had a nearly full Beta mag hit the concrete twice.

Under the advice of the RRAMod on the RRA forum, I removed the mag catch and bent it in a small amount.

Problem gone.

I think the issue is that the mag block side wall thickness is enough that the 223 standard mag catch just doesn't go far enough into the mag well to get a good purchase on the magazines.

Thanks to both of you.I think it shouldn't be a problem no more.

I had the same problem with my Mod1 kit. Problem is the "face" of the magcatch does not enter into the rec far enough to clear the magblock. After breaking the first magcatch by trying to bend it, the second magcatch only worked about 70% of the time(Not good enough for my needs). I took out my dremel, ground the finnish off the face of the magcatch followed by two oposing holes and a groove down the length. I then mixed some fresh JB weld (or equivelent) and slowly and carefuly built up the face (took a few layers) dremeled it flush around the sides it now works 100% all the time with a mix of Colt and promags. You do need to eyeball it to see how much more surface you may need. I sometimes wonder if A Colt MFG 9mm magcatch has more meat than a standard magcatch. Anyone know? This bending crap has to GO!!!!...................(My experience only/yours my differ)