Tuning Umarex M1A1 Thompson Repair

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1954

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Jan 4, 2020
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1
NY, United States
Hi. Posted this on Manufacturer Feedback as well.

Bought this March of 2020. Took good care of it. Have several Umarex replicas- they have worked well- no problem. Because of that didn’t by the service contract through Pyramid.

Safe to Fire position switch not working- gun won’t fire. There is a “ Field Strip” button at the end. I push it to release and slide the top portion. It will release but not slide off

Called Pyramid- said have to work through Umarex. Called them. Guy said- “ 90 day warranty, gun cannot be fixed, you will have to buy a new one”. Maybe guy was having a bad day.

Have texted Pyramid to see if they’ll exchange. Retired- don’t want to spend another $230.00. Probably just as expensive to fix. If Pyramid can’t help it becomes a wall hanger and conversation piece and a chance for buddies to hold a replica when we play pool.

Any thoughts? Thanks
 
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Not very much help Vetmx. Hey 1954, I have the same problem "BUT" before I take my M1A1 apart I want to KNOW that Umarex will "not" repair my BB gun. If they do not I will take my M1A1 apart and replicate any part that is jammed or broken. This is after all 2023, computer aided design( CAD) and prototype manufacture and replication (Laser cutter).
I suspect that it is a sear part (made of aluminum I can see it). I will also buy another M1A1. In any case; I will document the process for others so they can fix it.

3/6/2023 8:47am CST- I have a much better Macro Lenz so the new pictures will be much better.

Inked M1A1 jam.jpg


Inked M1A1 3.jpg
 
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Well I took the receiver apart (upper & lower) so now I can work on it It looks pretty straight forward. I tend to look at things and make them more complicated then they are really. I do not know if it is a little filing or more complicated. Anyway I can now work on it and find out what works.

So 1954 " Safe to Fire position switch not working- gun won’t fire. There is a “ Field Strip” button at the end. I push it to release and slide the top portion. It will release but not slide off."

I have attached a video of how to separate the upper and lower receiver less than a minute to do that.

 
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1954 said:
Hi. Posted this on Manufacturer Feedback as well.

Bought this March of 2020. Took good care of it. Have several Umarex replicas- they have worked well- no problem. Because of that didn’t by the service contract through Pyramid.

Safe to Fire position switch not working- gun won’t fire. There is a “ Field Strip” button at the end. I push it to release and slide the top portion. It will release but not slide off

Called Pyramid- said have to work through Umarex. Called them. Guy said- “ 90 day warranty, gun cannot be fixed, you will have to buy a new one”. Maybe guy was having a bad day.

Have texted Pyramid to see if they’ll exchange. Retired- don’t want to spend another $230.00. Probably just as expensive to fix. If Pyramid can’t help it becomes a wall hanger and conversation piece and a chance for buddies to hold a replica when we play pool.

Any thoughts? Thanks
Click to expand...
Well I took the receiver apart (upper & lower) so now I can work on it It looks pretty straight forward. I tend to look at things and make them more complicated then they are really. I do not know if it is a little filing or more complicated. Anyway I can now work on it and find out what works.

So 1954 " Safe to Fire position switch not working- gun won’t fire. There is a “ Field Strip” button at the end. I push it to release and slide the top portion. It will release but not slide off."

I have attached a video of how to separate the upper and lower receiver less than a minute to do that. See my post below for the video. Really easy.
 
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Well I looked at the M1A1 and decided on a process to repair it. I took M1A1 apart at least the parts that needed repair. I thought it was going to be more difficult that it was. I guess it would be called a sear (the part that stops/or allows) another round to enter the chamber or that stops the gun when the clip is empty. It is located on the upper receiver forward of the bolt. Took it apart a little bending (straight and a little filing, not much). I put it back together last night put a loaded clip in the M1A1 (NO Co2) and test fired and the bolt did not jam up. I am busy for the next two days so I will post the final test results. I am not positive that it is fixed so I did not take any pictures. If it passes the firing test I will take pictures.
 
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Vetmx said:
Roll up your sleeves and take it apart. Something broke and is jamming up the works. Who knows, maybe a BB found it’s way into somewhere bad.
Click to expand...
Most people (unlike people like us) do not have the ability of skill to repair anything. Use of tools, large tools or fine tools, and know the difference. I cannot speak for you but in high school I tool metal shop and electric shop. Those classes have served me well all of my life. I have also worked all of my with my hands all of life on one of many hobbies, sports or just fixing stuff. My point is that perhaps Member 1954 does not have the skills we have.
Just a thought.
 
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Well the Umarex M1A1 is working again I still want to make some adjustments to the sear, IMHO the sear could have been designed a little better although not seeing a new M1A1 Umarex may have already done that I do not know. These posts I am making do not appear to be of much interest so I will probably not be making any more. So I will still be posting on other topics so have fun with AIRGUNS everyone.
 
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I made the adjustments to the repair and it is working fine now. I also found the flaw that Umarex has in the M1A1, yes Umarex says that it uses the same mechanism as the MP-40, and for the most part that is true. However the inside of the clip chamber is quite different. Any way that is all for this post and my comments in it.
 
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ninersix said:
Well the Umarex M1A1 is working again I still want to make some adjustments to the sear, IMHO the sear could have been designed a little better although not seeing a new M1A1 Umarex may have already done that I do not know. These posts I am making do not appear to be of much interest so I will probably not be making any more. So I will still be posting on other topics so have fun with AIRGUNS everyone.
Click to expand...
 
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R.Ramjet said:
I'm following along and would like more info and see pics of your repair.
Click to expand...
As you can see this is the problem, the sear jams into the bolt slide and gets stuck; it sticks because it slides sideways and jams on the side of the bolt. In short it has worn the bolt and does not make direct flat contact. The bolt is made of "white metal not steel.

"White metal is sometimes known as Pot metal. Made from elements such as lead, zinc, bismuth and tin sometimes copper; white metal is commonly used for coatings of everyday objects like flatware, ornaments, bearings, medals, and household objects. It is easily cast and machined. It is softer than steel. Easily melted and cast into various parts."

In this case BB Gun parts apparently; it is also used in "fake Guns' or "Non Guns" or "replica guns' because it is MUCH cheaper than steel to manufacture and cannot be made to fire real ammunition, EVER." This is why when the steel sear hits the pot metal bolt at an angle it will eventually will carve away the at the bolt.
Below are the pictures of the problem.

M1A1 Jammed Top view.jpg


M1A1 Normal cocked.jpg


M1A1 Jammed side view.jpg

will
 
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Most of the small marks are just scratches not flecks of metal. The M1A1 that is pictured was cleaned of oil and metal shavings when I took it apart before the pictures were taken.

I have about 3.5k of BBs thru the M1A1 that is about 117 full clips- 30 BBs each. The same for my MP-40 that is about 64 full clips about 55 BBs each. The MP-40 has no signs of this same wear. So I really doubt that this indicative of all of the M1A1's out there. However I have absolutely NO idea how many Umarex M1A1's have been sold or made.

My opinion is if properly oiled (100% silicone oil) and maintained the M1A1 will last for a long time. If not I can always repair it.


My answer is YES, the sear and every part that moves on the M1A1 should be oiled even when stored.

I did not take pictures when I repaired it (because I did not know if the repair would work). So I will have to go over it again this time with pictures/video set up.
As I thought there was no interest in my posts I did not bother to do any recording(s) and so far there is only one other person that has shown any interest in these posts, You "R.Ramjet" have the unique position of being that one person.

As I related earlier my M1A1 repairable and is now working fine.

I do not know if I will have the time (to do a recording). I am a cybersecurity professional so I am kind of busy.
Doing videos/pictures takes time in pre and post production however; I will see if I can do another bit this weekend.

By the way I have to ask; "do you own an Umarex M1A1 or is this just an interest or interesting topic?" Just curios.
 
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ninersix said:
Most of the small marks are just scratches not flecks of metal. The M1A1 that is pictured was cleaned of oil and metal shavings when I took it apart before the pictures were taken.

I have about 3.5k of BBs thru the M1A1 that is about 117 full clips- 30 BBs each. The same for my MP-40 that is about 64 full clips about 55 BBs each. The MP-40 has no signs of this same wear. So I really doubt that this indicative of all of the M1A1's out there. However I have absolutely NO idea how many Umarex M1A1's have been sold or made.

My opinion is if properly oiled (100% silicone oil) and maintained the M1A1 will last for a long time. If not I can always repair it.


My answer is YES, the sear and every part that moves on the M1A1 should be oiled even when stored.

I did not take pictures when I repaired it (because I did not know if the repair would work). So I will have to go over it again this time with pictures/video set up.
As I thought there was no interest in my posts I did not bother to do any recording(s) and so far there is only one other person that has shown any interest in these posts, You "R.Ramjet" have the unique position of being that one person.

As I related earlier my M1A1 repairable and is now working fine.

I do not know if I will have the time (to do a recording). I am a cybersecurity professional so I am kind of busy.
Doing videos/pictures takes time in pre and post production however; I will see if I can do another bit this weekend.

By the way I have to ask; "do you own an Umarex M1A1 or is this just an interest or interesting topic?" Just curios.
Click to expand...
 
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