- Muzzle shroud
A muzzle shroud is a sleeve (either circular or otherwise) that extends beyond a weapon's muzzle.
Sound waves are semi-directional. They consist of both Point- and Line-wave propagation. The projectile emanates mostly Line-propagation properties after leaving the barrel. At the moment that the projectile is exiting the barrel it produces a mainly point-biased wave generation. (This is largely due to the shock waves traveling forward along the interior of the barrel, thus preventing any backward travel from the projectile into the barrel.) Sound waves travel in an ever-expanding bubble emanating from the muzzle when the propellant gases are traveling at supersonic speeds. This is called the "muzzle blast." Except in extremely low pressure loads, the exiting propellant gases generate much higher sound pressure levels (dBa) than any other aspect of the weapon firing. (e.g.: hammer, sear, bolt, supersonic flight signature, etc.) The supersonic "ballistic crack" is typically 136-138 dB, whereas "muzzle blast" may reach 168 dB. By encircling the muzzle, the shroud funnels and focuses the sound waves along the projectile flight axis, away from the shooter. This alone can partially protect the shooter from 12-18 dB of blast returning to the shooter's ears.
In the United States, the BATF has ruled that since the sound wave are not dampened and are metered at the same levels at two measuring points (1 m (3.3 ft) to the left and 0 m in front of the muzzle and 1 m (3.3 ft) left and 5 m (16 ft) forward of the muzzle) this is not a sound suppressing device. The only action which a muzzle shroud performs is shielding the area directly behind the muzzle from the worst blast pressures. Muzzle brakes direct the escaping gases rearward toward the shooter, thus increasing blast pressure directed toward the operator's ears. The same principle that lessens felt recoil also acts to enhance the sound levels reaching the shooter. Some of the muzzle brakes designed for heavy-caliber rifles (.338 Lapua, .408 CheyTac, .50 BMG) incorporate "blast shields" projecting laterally from the sides of the muzzle crown. Thus, reflecting sound waves traveling rearward via the muzzle brake blast chambers. These small leaves, however, do not fully enclose the muzzle diameter, and so block only the worst blast path, while allowing the majority of escaping gases to circumvent the shield by traveling around them, still reaching the shooter's ears, causing unacceptable hearing damage.
Wikimedia Foundation. 2010.
Look at other dictionaries:
Federal Assault Weapons Ban — The Federal Assault Weapons Ban (AWB) (or Public Safety and Recreational Firearms Use Protection Act) was a subtitle of the Violent Crime Control and Law Enforcement Act of 1994, a federal law in the United States that included a prohibition on… … Wikipedia
Spyder MR2 — paintball marker caption=A Spyder MR2 marker type=Electronic action=Open Bolt Blowback barrel=12 inch Muzzle Brake Barrel rof=25 bps price=$170 (MSRP)The Spyder MR2 is a paintball marker designed and manufactured by Kingman Group.DesignThe Spyder … Wikipedia
Spyder MR1 — paintball marker caption=A Spyder MR1 with detachable stock marker type=Mechanical(MR1)Electronic (E MR1) action=Semi Automatic(MR1)Full Automatic, Burst, Semi Automatic(E MR1) barrel=12 inch Muzzle Brake Barrel bore=.68 inches rof=Semi… … Wikipedia
Charter Arms Bulldog — 44 Special Type Revolver … Wikipedia
AK-74 — Infobox Weapon name=AK 74 caption=The AK 74M, the current rifle of the Russian Armed Forces origin=flag|Soviet Union type=Assault rifle is ranged=yes service=1974–present used by=Soviet Union, countries of the former Warsaw Pact wars=Afghan War,… … Wikipedia
Dan Wesson Firearms — Type Part of the CZ corporate group Industry Defense Products Services Founded 1968 … Wikipedia
Rheinmetall MG3 — Karar redirects here. For the Iranian unmanned aerial combat drone, see Karrar (UCAV). For the Chinese made car, see MG 3. MG3 MG3 Type … Wikipedia
Assault rifle — An assault rifle is a selective fire rifle or carbine (not to be confused with a semi automatic only replica) firing ammunition with muzzle energies intermediate between those typical of pistol and high powered rifle ammunition. Assault rifles… … Wikipedia
Gewehr 98 — with bayonet and 5 round stripper clip on the side Type Bolt action rifle Place of origin … Wikipedia
literature — /lit euhr euh cheuhr, choor , li treuh /, n. 1. writings in which expression and form, in connection with ideas of permanent and universal interest, are characteristic or essential features, as poetry, novels, history, biography, and essays. 2.… … Universalium