Loud enough is my M91-30, most people at the range sighting in various rifles seem to pack up whenever I drop by. As the rifle and I warm up and my groups get smaller(Current record 1.72"@100yds), theirs get bigger. Particularly with the WW2 Russian surplus ammo, its noticeably hotter than the 1980's Romanian I usually feed it. Either way, you don't want to be standing next to me when it goes off, the shockwave hits you in the face hard enough to feel it in your cheekbones. A lot of it probably has to do with the very slow powders most surplus is loaded with, you can see the 3ft muzzle flash in daylight.