So far, 10.5" Tromix upper has been flawless. Blasted through ~50 rds of my wide meplat plated bullet reloads, shot over 100 rounds of 450g FMJ's for load development, and put a few fat nosed 405g lead boolits downrange as well with nothing to complain about. Getting very close to getting a decent subsonic load for the 450 FMJ's as well. Going to test out some AA9 this weekend and hoping that is "the" powder for it. I posted more info about that on 458socomfoums dot com for any interested parties.