Roller-delayed blowback
From Wikipedia, the free encyclopedia
Roller-delayed blowback is a firearm operating principle, a refined form of blowback. The main proponent of the system, Heckler & Koch, also referred to it as roller-locked, although the rollers delay, rather than positively lock, the bolt.
Roller-delayed blowback is not to be confused with roller-locked recoil operation in the MG 42, for example, where the bolt is rigidly locked to the barrel as it recoils. In roller-delayed blowback, by contrast, the barrel is fixed and does not recoil at all. The fact that the barrel is fixed and does not have a gas system attached is considered a theoretical advantage for accuracy, since this allows the barrel to be truly "free floating."
Roller-delayed blowback was first used in experimental MG42 derivatives and a 1945 Mauser Sturmgewehr prototype. It then made its way via the Spanish CETME to Heckler & Koch, where it was the basis for much of its product line from the 1950s onwards. Although one of the original motivations for developing roller-delayed blowback was simplification for ease of manufacturing, it requires precision machining of the rollers and bolt head, particularly for high-pressure cartridges. More recent HK firearms, beginning with the HK G36, are mainly gas-operated.
The main examples are the Heckler & Koch HK G3 and HK MP5.
[edit] List of roller-delayed blowback firearms
- Mauser StG45(M) Sturmgewehr prototype
- Swiss SIG 510 rifle
- SIG MG 710 GPMG
- HK PSG1 precision rifle
- HK P9 pistol
- HK 21 machine guns
- HK G3 ("Gewehr 3")
- HK MP5 series SMGs
- CETME Rifle Series "Fusil de Asalto"
[edit] References
MG42V and the Origins of Delayed Blowback Roller Lock: WWII German Equipment (Paperback) by Derek Bremner. ISBN 0953379205
