these guys have pretty much summed it up... I will add, it does reduce the felt recoil alot... perhaps both because of the additional weight at the muzzle, & the ports... I have both a 338 Win Mag & a 375 H&H Stainless Stalkers, both with BOSS... both are more accurate than I am, & neither one is much different than shooting a .308 / 30-06
BTW... I don't personally think it's louder than the same rifle without the BOSS & with a 2" shorter barrel... the ports are not angled towards the shooter, so the "effect is no different than a 2" shorter barrel
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