Tuning Umarex M1A1 Thompson Repair

Now comes the the fitting for Stock.

I think I missed posting the M1A1 Stock from King Arms, what can I say it's Tax time.

Anyway this was the most fun I had on the project of fitting the wood King Arms stock to the Umarex gun. I had to cut a channel down into the head of the (the part that is closest to the gun) stock so that the Umarex extended lateral bolt hole would accommodate the Umarex gun. Along with a center point that the trunnion bolt would be centered and fit. I also had to enlarge the round trunnion bolt ends as apparently the AirSoft ones are a bit smaller.
Little did I know at that time that I would not use the trunnion bolt at all. Why: because I didn't need it. That two long metric machine bolts would hold the stock with more that enough strength. So after I made a new trunnion bolt along with the two new side pieces I decide NOT to use it. I had made two silicone rubber molds and since I had cast more that two sets I just used the two side disks and glued them in the holes provided. You cannot tell the difference between the poly plastic pieces from the metal ones.

I used a very small saw (Japanese actually), then with a 1/4 inch chisel cut the excess out of the channel I needed. The markings are the channels with a centerline where the trunnion bolt goes. Then I needed to plug the old holes where the King Arms bolts would have gone and drill new holes for the M6-1.0x40 and M6-1.0 60 go in the Umarex gun.

I also needed (well I did not have to) fill the hole running down the center of the stock with a 1 3/4 inch long round wood peg where the battery wires would go thru the King Arms stock to connect to the Airsoft gun, the King Arms stock had an empty space . I also filled the rather large hole towards the front of the gun and the rear bolt was not solid wood (bad) for structure of the stock. I did this so the wood was solid where the bolts would go thru the stock and not have any air space the could cause a weak space in the stock.
Then all I had to do was to drill new bolt holes that aligned with the Umarex gun. That's it and done, except for the striping, staining and polyurethane coating.
Man, three (3) coats of Dark Walnut stain, 24 hours for each coat to dry, then two coats of poly, again 24 hours the thoughrilly harden. All of this too only about 15-20 minutes, the rest was doing other things.

Adding wooden furniture also adds a few hundred more FPS of BB impact as well.

So in the end it all worked out, the M1A1 Umarex looks great and feels even better. And by removing only two bolts on the stock I can remove the stock and fit the entire gun into the Replica WWII bag without using the extension on the bag for the barrel. (Which was always a pain by the way.)
I am very happy with the results of the project.
Note: I cannot believe how this has changed the look and feel of the M1A1 gun... It is amazing to me even now! Well worth the time and expense I put into the project.

I am wondering about the M1 Carbine (Paratrooper version) If they (anyone making a Co2 BB .177) makes an automatic version? I would like to put wood grips on that also. It is WWII and many of the M1 carbines were made to fire single and auto (curved 30 round mags.). I will have to think on that.

Northwoods22 said:

First choice would be the German Fallschirmjager rifle, the FG42 2nd Pattern. Second would be the Sturmgewehr 44.

View attachment 378040

Click to expand...

Northwoods:
I am good with the Sturmgewehr as it is and was the FIRST mid caliber "Assault weapon" Hitler's words not mine. So there is no question that it is a historic weapon. The Fallschirmjager rifle, FG42 was an attempt but so few were made and it had a few fatal design flaws not the least of all jamming during combat needing repair. Anyway that is my opinion not as historic as the Sturmgewehr and so few were made about 5000 and the procurement was very unorthodox even WWII Germany.

I wanted to add one thing about the completed wood furniture on M1A1 Thompson by Umarex, now that it is completed. . . . . . I LOVE IT! It gives me the look feel I sought after, realistic and just... words fail me. I also can now fit it into the Thompson replica bag (same one as the M3 Bag).

I am going to my friends house in about a week to shoot our guns (he has the MP40 I gave him for his birthday), I am bringing my three M1A1, MP40 and M3 with me. He will fly to my local airport pick me up fly to his house.. then a little Bourbon and cigars and I show off my M1A1 etc.
We will do some shooting I will give him some tips and tricks, care and feeding instructions, silicone oils. then we will do some target and play a GAME.
The Game:
We will use Plaster Tanks in a shortened game (we do have rules) I should share some pix's of the tanks. they are plaster painted of course 1/32 scale, in fact I should show you some.

I did not include the halftrack's or the Hetzer tanks or the Valentine Tank (British Tank). Like I said small battle. Just two guys re-fighting a WWII battle with our Legend's Guns.
I still cannot get over how GREAT the M1A1 looks and feels!

I wanted to post this video I made before I did the the final staining and poly coating... but with taxes and Cybersecurity small jobs; I just forgot about it.
So here it is (Youtube). Remember the M1A1 does not have the final finish on the wood Furniture like it does in the previous pictures. I hope it gives a better idea of the modifications I made to the wood furniture as I show you everything.


I should really do a better video, I was using a older camera on this one or the Lenz was just dirty.

R.Ramjet said:

Adding wooden furniture also adds a few hundred more FPS of BB impact as well.

Click to expand...

Sorry R.Ramjet; this post of yours slid by me and then I got really busy and ... well I am sorry I missed it. But here is my answer; I did not see any difference in my tests that any change in velocity takes place by removing the sock (I did test it for velocity and aiming without the stock, no effect).
I wonder why you think that would happen?

It is only the BB gun's magazine with the Co2 and chamber that has any effect on velocity except something obstructing the barrel of chamber on the magazine. So no effect on velocity of BBs is seen.

However when my friend and I finally got together and did our shooting I did notice that there is a large discrepancy between individual magazines! I have 4 (four M1A1 mags) I tested them when I got back home with full C02 loads and shot them until they were exhausted of Co2, that is about 6 full loads for each magazine. The result was a surprise for me! Mag 2 ran out of C02 first, (I have them numbered), then N0. 3 ran out first next, then N0. 4 rand out while shooting at a much slower rate of fire (it sounded like the real M1A1 @900 rpm) which I really liked. No. 1 (original came with gun) was a power house it kept on firing sometimes shooting 4-5 bb's at a time (it was also the most used Mag, "oldest") it went to seven re-lodes.
I was surprised at the difference in performance between each of the magazines. I also noted that the M3 magazines and the MP40 magazines had some similar things going on as well only not as pronounced.

So I would like to have the M1A1 shoot at the same auto fire as the real M1A1 did, about 600 - 900 rpm.
So I will have to see, I really want to see if I can change the firing rate, I would very much like the M1A1 Thompson to feel act, and sound like the real thing. Of course it is a Co2 BB gun after all. I think it is possible. I am just so happy with the wood furniture; love to see the M1A1 act like the real one as much as possible for a BB gun.

ninersix said:

Sorry R.Ramjet; this post of yours slid by me and then I got really busy and ... well I am sorry I missed it. But here is my answer; I did not see any difference in my tests that any change in velocity takes place by removing the sock (I did test it for velocity and aiming without the stock, no effect).
I wonder why you think that would happen?

It is only the BB gun's magazine with the Co2 and chamber that has any effect on velocity except something obstructing the barrel of chamber on the magazine. So no effect on velocity of BBs is seen.

However when my friend and I finally got together and did our shooting I did notice that there is a large discrepancy between individual magazines! I have 4 (four M1A1 mags) I tested them when I got back home with full C02 loads and shot them until they were exhausted of Co2, that is about 6 full loads for each magazine. The result was a surprise for me! One mag ran out of C02 first, (I have them numbered), then N0. 2 rand out next, Then N0. 3 rand out while shooting at a much slower rate of fire (it sounded like the real M1A1 @900 rpm) which I really liked. No. 4 was a power house it kept on firing sometimes shooting 4-5 bb's at a time, it went to seven re-lodes.
I was surprised at the difference in performance between each of the magazines. I also noted that the M3 magazines and the MP40 magazines had some similar things going on as well only not as pronounced.

So I would like to have the M1A1 shoot at the same auto fire as the real M1A1 did, about 600 - 900 rpm.
So I will have to see, I really want to see if I can change the firing rate, I would very much like the M1A1 Thompson to feel act, and sound like the real thing. Of course it is a Co2 BB gun after all. I think it is possible. I am just so happy with the wood furniture; love to see the M1A1 act like the real one as much as possible for a BB gun.

Click to expand...

Thanks guys for the likes. Reactions: Sawney Bean, borne2fly and gendoc