Thompson carbine

The gun was made by at least two different companies.
The first was Volunteer Enterprises of Knoxville, TN, made before 1978.

They made the Commando Mark III in .45 and the Commando Mark 9 in 9mm.
The .45 is worth about $750 in brand new in the box $525 in 90%.
Add 10% if it has the vertical front grip.
The Volunteer version did not have as bad a reputation as the later guns made by Commando Arms, but these were not particularly high quality guns, and many had reliability issues.

No parts are available.

Here's some sites with more info:

http://grungebag.webs.com/manualsandinfo.htm

http://www.freewebs.com/grungebag/

local indoor range had a 45cal commando jamamatic as a rental. it was reasonably accurate and sometimes you could empty two whole clips without problems

Had the Commando Arms in .45 many years ago....All I remember is that it worked well.
But it was not what you would call a quality piece.
I traded it in for a I believe Numerich (spelling?) Arms Thompson with the aluminum receiver.
That one looked way better, but the bolt would stick so bad that even a rubber mallet would not dislodge it.
The gunny said that they needed lots of oil.
I traded that for an HK 94 which had no such problems.

Oh, well. Got one. Just got thru a few months ago on a full restore. Nice walnut wood, cast alum lower Mark 3 .45. If you want a neat gun for the wall get it. If you want to shoot it and it has a plastic lower DO NOT get it. It will break. If you can find a metal one they are fun to shoot: forged barrel, simple sub-structure(two-inch recoil buffer) except for the firing pin. All it did, when I last shot it 30 years ago, was spit out .45s with considerable accuracy. I was shooting at an disused toilet. What fun. No jams, and those grease gun magazines were cheap,too. Hope this helps.