M41A Project

[Gold1927a1]

I'm planning on buying a TM1C rifle to SBR and use as the base gun. Just wondering how big the issues are with the aluminum receiver guns?

There are listings for blem guns at discounted prices at the moment. The lighter weight would be preferable for this project.

The title isn't a typo.. more to come.

 

[68coupe]

In my humble opinion, aluminum has more of a tendency to stretch and/or deform, regardless of alloy. Again, IMHO, put up with the greater mass and buy a firearm built to last (not that Kahr's are even built to run properly). You may have better results (luck) than many others have had. I had descent luck with mine, but it still required some tuning to make it run well, thanks to Dan, "Deerslayer". Simply put, aluminum is great for aircraft, but not so great for firearms.

Karl, 68coupe

[BillyDixon]

what is an M41a, ?? just askin

[Gold1927a1]

It's a live fire prop gun from the greatest sci fi movie of all time. Made from a Thompson as the base gun.

M41A

 

[TSMGguy]

On 7/3/2025 at 7:26 PM, 68coupe said:

....aluminum is great for aircraft, but not so great for firearms.

Karl, 68coupe

Unless of course it's been forged, like M16s and M4s. Works pretty well then. 

[Keith Johnson]

My 20 round GI mag works quite well in my West Hurley semi auto Thompson.   I had to open the locking hole on the back of the 20 round mag but it locks in place and feeds rounds just fine.

[Gold1927a1]

Slowly but surely I'm going to start accumulating the necessary parts for this build. 

Today the magazine baseplate came in the mail, alone with a guide rail to assist in feeding the mag into the clamshell.

Ordinarily these parts are for the airsoft guns or replica builds the movie fans make...

but since the base airsoft gun used in the evike/snow wolf pulse rifle is a Toyko Mauri it's nearly identical dimensionally to the real Tommy gun.

 

I was originally going to just reuse most of the plastic parts of the fake launcher, etc but there's tons of real steel/aluminum prop parts on ebay and I think that when all is said and done, it's going to be worth the extra expense for the metal parts. I'm sure there may be some custom fitting but it looks like the aftermarket steel stocks just need a few holes drilled for the collapsed/extended position lockups.

As far as the main clamshell, it's strong enough as is but I'll probably reinforce it with jb weld or something. 

[SparksNArcs]

I'm working on the same thing, but I'm curious where you got the magazine base unit from? It looks really good! I'm using the SD Studios parts to start mine: stock, grenade launcher end cap and eventually the barrel shroud stuff. The expensive part is going to be the SPAS cage, as there's only one guy making them apparently and they cost $300 plus shipping from the UK; he also makes the pump handles to go with the cage.

Edited September 14, 2025 by SparksNArcs

[Gold1927a1]

Got it from ebay user  vennmodels. Ask him to 3d print the base solid for a real mag. Funny thing is the real mag fits better than the airsoft mag lol.

Funny coincidence, I'm going to use all the same parts. If you let the parts sit in your cart for a few days you get auto offers for the parts a bit cheaper.

We can work off eachother's ideas on how to make this thing work. I do have a little flux core welder than works great for thin metal, but screw build will probably work also.

Any thoughts on reinforcing the clamshell? I already had the airsoft gun for years just sitting around and it feels pretty sturdy.

[Gold1927a1]

Also you can get extra factory base plates from evike. There is a color discrepancy with the ebay bases but they work well. I'm thinking I can insert a mag and put some jb weld in the bottom of a factory base plate and just stick it on and let it dry.

Going to have to take a look at the ammo counter and see if I can wire it to work with real ammo.

[SparksNArcs]

The original counter circuit uses a photo diode setup that interacts with the electric motor and gear train from the airsoft M1A1 from what I understand, which doesn't do any good in a real firearm. It might be possible to connect a reed switch instead, I'd have to play with it but I've got other projects to work on right now. Another guy I saw online bought a custom 20rd counter and used a magnetic reed switch and a magnet attached to the charging handle to run the counter.