I got out and did some shooting today and tested 3 designs of muzzle brakes on my 338 Nawakwa (338 lapua imp) I was shooting 300g Sierra match kings with 100g of Retumbo. The first shot was with a standard brake the second brake is one of these
and the last brake is the same as the second but the ports are angled back here is the video
YouTube - comparing brake designs 338 nawakwa
and the last brake is the same as the second but the ports are angled back here is the video
YouTube - comparing brake designs 338 nawakwa