Spent two days shooting my M&P15T over the holidays (I didn't know that this forum existed yet - so forgive the tardiness). During those two days I put about 300-500 rounds through it without cleaning it, not even a boresnake through the barrel. I had a bit of problem with it but after some mild filing at the range between magazines, it ran nicely. We were shooting and moving, the temp was in the 50s and it was very humid, mud everywhere. I was pleasantly surprised at its performance, especially given the fact that we were shooting Ak's side by side (put about 1000 rounds through them in two days). The 15T was so comfortable and a natural pointer, that it was hard to miss at the distance we were shooting at (about 15-25 yards). At any rate, it is a lovely gun.