Blow-forward is a firearm operation type where the friction and pressure of the bullet traveling down the bore drag the barrel forward.
This mechanism requires that the remainder of the firearm recoil away from the barrel for proper operation. Due to the reduced mass of rearward-traveling parts coupled with the increased mass of the forward moving parts (barrel in addition to bullet and propellant gasses), recoil energy is significantly greater than other operating mechanisms. The barrel and spring are generally the only moving parts. The operation can be best characterized as a combination of recoil and blowback operation.
Although blow-forward firearms are unique and interesting, the mechanism was only developed in the early stages of repeating mechanism design when firearm designers were experimenting with different methods to make small repeating arms. Blowback and short recoil operation were deemed cheaper, more efficient and more reliable, so blow-forward firearms have not been built for many decades.
The first blow-forward firearm was the Mannlicher M1894 pistol. The principle has been used in a few other weapons, including:
- Schwarzlose Model 1908
- Hino Komuro M1908 Pistol
- SIG AK53 battle rifle
- Pancor Jackhammer automatic shotgun
- Mk 20 Mod 0 40mm automatic grenade launcher.
- Hammerfell, Richard (7 March 2015). Firearms Illustrated - Pistol Edition. Digital Services. p. 166. GGKEY:PKJGL3K97WH.
- Smith, B. (7 March 2015). History of the Handgun. Digital Services. p. 1896. GGKEY:5F3APLD7J8C.
- Cunningham, Grant (2012). Gun Digest Shooter's Guide to Handguns. Iola, Wisconsin: Gun Digest Books. p. 22. ISBN 1-4402-3276-8.