Ok, my M&P-10 7.62 is my current night gun with a thermal optic. I love it! It’s reduced the pig population at my ranch quite effectively. However I “need” a day gun with an optical sight. I want a larger bore too. 7.62 is a great round but pigs are tough bastards. I want to use my PSA 5.56 AR-15 lower. I’ve read allot about all three cartridges and it seems the .450 Bushmaster has the best over all numbers for raw hitting power and accuracy. So, I found a Rock River complete upper but I’m verifying they can actually deliver in a reasonable amount of time because all uppers are assembled on order. Any comments before I throw down.