Monday, September 26, 2011

The Hino-Komura pistol

(Image source)
A design from the early days of semi-automatic pistols is the Japanese Hino-Komura pistol of 1907.  The Russo-Japanese War was a triumph for the Chrysanthemum Throne, but it convinced the Imperial Japanese Army that it seeded a self-loading pistol.  You see, all the Cool Kids were getting them.

But the new-fangled things were, well, new, and so nobody really knew what worked best.  And so the Hino-Komura ended up with the marvelously quirky blow forward design.  The breech was solid, an integral part of the frame.  It was motionless when the pistol was fired, and the barrel was what moved.

The friction of the bullet is what drove the barrel forward.  Eventually the bullet left the muzzle (removing further forward impetus) and a recoil spring slowed and stopped the barrel's forward motion.  At this point, the ejector kicked away the spent case - which the extractor had been holding firmly in place against the breech - and a fresh cartridge was seated.  Then the spring returned the barrel, cocking the firing pin.

Alas for the Hino-Komura, it was not accepted for use by the Army, and only 1200 or so were made.  Highly collectible, a cache of 17 were found in a Japanese warehouse in 1992.  Sadly, there were destroyed rather than being sold to collectors.  It seems that one lucky collector found one in a box of random stuff at a garage sale, and picked the lot up for $20.  That's winning the lottery.

A few blow forward designs were implemented, perhaps most famous being the Mk 20 Grenade Launcher used in Vietnam.  Manlicher also had a commercial design in the 1890s, and Schwarzlose had what was perhaps the only commercially successful offer.  Why?

One objection is what to do if the gun does not return to battery (i.e. the barrel or breach does not fully re-seat).  In your typical blow back design (1911 style), you just hit the back of the gun, and it will likely be enough for the pistol to re-seat.  That won't work on a blow forward design - you have to smack the barrel back towards you.  In the event of a slam fire, the part of you that you use to smack the barrel is in front of the barrel when the pistol fires (oops).

And so we only see blow forward designs in the early days of auto-loading pistols, before everyone figured out what worked better.  While things are cheaper and more reliable now, they're more similar.  Functionally this is a big win, but a little of the poetry got lost along the way.

But maybe I need to start going to garage sales ...


ajdshootist said...

Thanks thats a new one for me never seen or heard of one have fired a Nambu did not like it.

New Jovian Thunderbolt said...

Thas a hansum lil furren pistol, I must say.

45er said...

That's super-kooky and super-cool. It also looks super-dangerous, but I'd still love to have one for collection purposes.

Nathan Tramp said...

The innovative-looking "Pancor Jackhammer" shotgun was also a blow-forward design, so there are a few examples of this in the modern age.