I've had my RDB for 2 weeks now, and have attempted to put 600 rounds through it in two seperate trips. Serial is ZOZxx, and appears to have all the recent updates. Upon receiving it, I cleaned/lubed everything but the gas piston, and did not remove/strip the bolt for cleaning. I got an awesome 200 rounds through the gun, and then began getting some failure to feed. In the next 100 rounds of that 300 round session I had 9 FTF. The cases were bent in the middle with a gouge mark. They all came out easily by running the charging handle until they dropped out. Today I tried another 300 rounds. I cleaned all parts of the gun this time, as well as the magazines which are 30 round gen 2 Pmags for all rounds before, and this time. I also brought some GI mags. The Pmags all had 1000 rounds of suppressed shots through them and were filthy, but still functioning fine in both of my AR's, but after the FTF's I figured I should start clean this time. All the Pmags ran fine this time except for one which produced less, but the same FTF's. I disassembled the Pmag, and stretched the spring. It functioned fine after that. The GI mags would fire one shot, and then release from the mag catch, but not fall free closing the bolt on an empty chamber. Overall I got the gun very hot, and shot 296 rounds trouble free. I really love the concept, and the way it handles live fire. I'm hoping as it breaks in, it will become more forgiving with Pmags at least, as that's usually all I use and have tons. I will suppress this gun when I get another muzzle device for it soon. This is my first bull pup, and my first Keltec. Happy shooting!