Hi. I just bought a Howa carbine. It's the military model used by the Thai Royal Police. It has their logo imprinted on the receiver ring.
I'm looking for someone else that owns a Howa to compare this carbine with. I suspect a prior owner used a walnut stain on the stock. There are also some markings on the right side of the receiver at the rear above the recoil spring housing that I can't make out. The only Howa marking on this carbine is on the bottom of the barrel under the slide, the letters HP, which I understand is one of the Howa trademarks.
War Baby Comes Home pp. 729-732 shows the commercial variation manufactured by Howa, the Model 3000 Autoloading Rifle.
The way I see it, Howa was and is a privately owned company. They were initially contracted by the Japanese government to produce M1 carbines for their security forces. At some point they exported the carbine. At some point they came out with a sporterized version.
Plainfield Machine, Bullseye Gun Works, Universal Firearms, National Ordnance, and Millville Ordnance were all private companies that sold carbines commercially, but they also received contracts from the police and military of foreign nations. Also, the police here in the USA.
I recall something about Winchester or Inland considering commercial carbine production, but events made them change their mind. All 10 primary contractors that made the original GI carbines were private companies under contract to the government, solely because we were at war. Like most all government contracts, the government set the standards and acceptable price range. Keeping in mind only one, Winchester, was a gun manufacturer.
The M1 carbine can be used as a fighting rifle, so can a Ruger 10/22. It was never meant to be a main battle rifle, just an option for those stuck carrying a handgun. Yes, it was used beyond it's design and purpose, which is why a whole lot of GI's in Korea absolutely hated them. Not the fault of the rifle or cartridge. Ownership for that decision goes to whoever allowed them to be issued in place of main battle rifles. The outcome was highly predictable. For urban warfare, like police work, it's a pretty decent weapon.