Muzzle Blast
The pressure wave and concussion released at the muzzle when a shot is fired, intensified by brakes and short barrels.
Muzzle blast is the sharp pressure wave and concussion produced as high-pressure gas follows the bullet out of the bore. Its intensity rises with chamber pressure, with shorter barrels that release the gas while it is still energetic, and especially with a muzzle-brake, which redirects that gas back toward the shooter and any nearby observers. A muzzle-device that tames recoil often makes blast noticeably more intense.
The practical cost of blast is felt as concussion and noise, which is why a brake on the firing line can be punishing for shooters on either side. A silencer reduces blast by bleeding the gas off gradually inside the can, and proper hearing-protection remains essential whenever a brake or short barrel is in use.