Ive got the Rock set curing right now. Fortunately MI didn't slather rockset on their brake with a fire hose and torque it with a 20' cheater bar. Their muzzle device came right off. I will take it out for a range test tomorrow after the rocksett has had at least 12 hours cure time. This method has worked for both Scars so I am confident. I am excited to see what all the fuss about 220's and and silencers.
I couldn't tell much of a difference in sound between the 220s and the 187gr gemtechs. I can tell you that both have a tendacy to flirt with the sound barrier from time to time. Doesn't bother my ears but they are noticeably louder. They are not as quiet as I expected them to be but maybe my expecations were unrealistic. I was going off the air rifle comments. I mean it's certainly the quitest big bore I own but... You get the idea. Either way I am looking forward to laying into a pack of hogs with it. I managed to hit the 300 yard yard gong with it. Not much impact at that distance. At 100 it thwacked the crap out of the AR500 target. Much louder then the bullet leaving the barrel too. My pops was 600 yards away on the other side of the woods and he told me all he could hear was the steal being struck. That's good news.
So when you are shooting it you hear about 130db because of the action and buffer. If you stood beside someone while they were shooting it then you would get a better idea of what it really sounds like.