I got to push it really hard this past Saturday - 350 rounds in a little under and hour or so. I can say the dirtier it is, the more you can feel the blast our of the ejection port. It's not bad, but you do notice it when you're standing right next to the ejection port. I did manage to push it to the point where I go the two failures to feed with HPs. The first was the Gold Dot and the other with the Hornady, both didn't seem to get picked up by the bolt, and got caught on the edge of the feed ramp. This was after 100 rounds of the Blazer and 100 of AE 147 grn. 50 of the Speer.
Both of the failures were the last round in the mag. I got one failure in a Metalform mag, and one failure in a Brownells mag.
I suspect that if I kept running FMJs I wouldn't have run into this issue due to the different shape of the heads.