BLOW FORWARD ACTION

No, it is not a mistake made when I meant to write blow back, nor is it some kind of clever word play. There is such a thing as a BLOW FORWARD action and its operation casts some interesting questions on shotgun action wear.

So what is this Blow Forward action?

It is the phenomenon of the forward thrust, perhaps pull might be a more accurate term, effected by the powder gases and the projectile as it travels down the barrel. The phenomenon is seen when the breech is fixed and the barrel free to move. Visualise a gun with a stationary breech and no lock up with the barrel. A spring pushes the barrel against the breech.

On firing the gases push the load towards the muzzle. The same forces also pull the barrel forward, away from the standing breech. It is a paradox in guns, considering how we have been conditioned by countless books and articles to assume that the only forces inside a gun are always directed backwards, towards the breech. I was surprised to discover the Blow Forward action while doing a search for the friction component in gun barrels.

Several guns utilise the Blow Forward system. Perhaps the most well known is the German made Schwarzlose pistol, but there are also the Japanese Hino Komuro pistol, the Steyr Mannlicher 1894 pistol and the German HK53 rifle. All were operational guns that went into production.

The existence of the Blow Forward phenomenon obviously exists in all fixed breech guns. The question that came to me as I read about it and watched the videos, is how this phenomenon affects wear in shotguns, especially break action shotguns. If the Blow Forward phenomenon is powerful enough to operate a pistol firing the diminutive 0.32 round, then it must exert considerable force on the cross pin of a double firing 2 3/4 inch cartridges. That must affect how the pin and the barrel hook wears.

The Forgotten Weapons people have posted several videos on the Blow Forward action the pic is from one of those videos. You can see the full video here: