I have used the UBR stock on my MP10, with a JP enterprises captured recoil buffer setup. go that route, you will have no problems. this setup combined with the Syrac Ordnance adjustable gas block makes this rifle shoot like a dream.
I recently added a 12" Apex hand guard and used the clamp on type of gas block. DEFINITELY the way to go. I read somewhere that they offered a tighter gas seal.