I have the 527 suppressor ready in 300 blackout. It?s a nice, handy rifle. While I was tempted by the 7.62x39 in the suppressor ready (I also have a 527 carbine in the x39), I ultimately went with the blackout as I mainly was after quiet subsonic suppressed loads. The 7.62x39 has the .311 bore, I believe vs. a .308 bore on the blackout. Much larger selection of .308 diameter projectiles to choose from to load subsonic. If shooting supersonic is your aim, it is hard to beat the economical surplus 7.62x39 ammo availability.