So I was dead set on getting a 5.56 upper for my SBR build but now I'm debating if I should really good the 300blk route. I've already spent too much money recently so I can't do both now. Should I go 5.56 and get a AAC 556SD or go 300blk and get a 7.61 can? I know people will say get the 7.62 can regardless but if I'm not going to get the 300blk upper I'll pass on a .30 can for now due to price. Cherokee has the AAC 556SD for $450 and the Specwar is $700 so for $250 I can pay my stamp and still have $50 left over. Also .300 ammo is hella expensive. Plus side is I dont shoot much but goodness its like a buck a round and I'm probably too cheap for that. I know that its quieter than 5.56 but how much more so? I can't find any decent comparison videos but is 300 blk backyard quiet?