Had my second case head failure with the same lot of brass yesterday. Gun is a Para P-16 Limited with Dawson magwell and base pads. Load is Federal (supposedly) once fired nickel Brass that the seller had roll sized.Loaded with a 180 gr FMJ over 5.3 gr Bullseye. The first seperation was uneventful, the gun simply went bang with a slightly different sound so I stopped shooting to rack the slide and the remains of the case were stuck in the chamber sans case head. Released slide and retracted again and the rest of case ejected (gotta love that Para PXT) and the gun was fine. Yesterdays was more dramatic, the gun made a differet sounding bang and proceded to blow the Dawson base pad, spring, follower and the remaining 17 rounds out of the gun. and my left index finger and thumb were stinging. The case was bulged and shredded at the bottom with a piece peeled down and laying flat on the barrel ramp. the case head was located on the ground in the neet little pile of bullets and mag parts at my feet. it looked to be in perfect shape and showed no signs of overpressure around the primer, it was simply cleanly sheered around the inside portion of the extractor groove. My hand was fine just a little rattled. After inspecting the gun and magazine everything looked good. I put it all back together and switched to factory ammo and shot the next stage using it. Needless to say I am not using that brass any longer.