So, to answer the ongoing question. I put a PSA, P10 upper on this lower. It fits, kinda. There is a slight gap at the top of the lower, and the charging handle prevents the rear takedown pin from fitting. The solution is easy, use the speed bore to remove 1/8" off the top of the lower, where the buffer tube threads in. Lastly the takedown pins included with the PSA build kit are long enough to function, but are about 3/16" short of being flush. All said and done, it's a solid rifle, and perfectly functional.
