CalNewbie, Ahhh, I see. I think that's what NoMercy was getting at...CR (closed) vs. muzzlebrake (open). I actually don't use the CR attachment. I still think the BOSS benefits even those who handload (I handload a little). The BOSS system gives you the versatility to shoot more than one handload (165gr vs. 180gr.) You can have more than one "sweet load."