My first 458 lott had a 21" barrel which included the muzzle brake. Muzzle blast and concussion weren't an issue. My son's 243 has a 20" barrel and I worked up some loads with H-335. Talk about muzzle blast and concussion!
It's been my experience that the medium and large bores tend not to have excessive muzzle blast and concussion. It's the high stepping small bores that make the racket. The worst offended I've seen was a braked 30-378 Weatherby. My luck was the only free bench at the range was next to that guy, and I didn't end up shooting that day as the concussion was intolerable.
