MGC Thompson Collector's Armoury Cut Bolt Resurrection

Post by ljerr2

Hi guys. I recently bought an MGC Thompson off ebay. I screwed up. It was one of the models imported to the US in the 1980's I believe, so the bolt has been cut and there is no chamber/detonator.
My question is, it appears that I can replace the bolt assembly and install a chamber/detonator and be in business. The ejector is even in the gun.
My question is does anyone know if that is all that was done to these guns and therefore is a bolt replacement and chamber install all that is necessary to return this item to a firing model?
Thanks.

Post by figaro

Mine was similar, it also had a post blocking the chamber from below, that I drilled out fairly easily.
I bought a brand new bolt from Franky, but the ejector arm is huge and not removable, and thus the bolt does not fit in the place of the old one.
I could dremel/mill the inside of the upper receiver but that's not really my bag, and really quite a job as you would have to dremel at an angle (the ejector sticks out at 45 degrees.

before buying a new bolt, be aware you should check, you might also have to do this to your replica, but you may be more qualified than me to do this kind of work 9and you might find an old style bolt).

With a detonator installed in the chamber there seems no reason why it shouldn't work after replacing the bolt.
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Post by ljerr2

Figaro,
Thanks for the input. I think I remember reading a previous post where you had encountered the bolt interference issue and I was making note of that necessary modification.
Has anyone actually modified the upper receiver for this purpose? I don't mind using a dremel, but it would be hard to achieve consistent results unless only a small part of the receiver material needs to be removed.
Thanks.
JL

Post by shazhib

ljerr2,

I have both current type and old type (open barrel) receiver, maybe I can send you a photo and where you need to Dormel (Dremel?).

Now, if you want to fire, what kind of parts you need? bolt? chamber? is that open barrel? is that the version you screw from top of upper receiver or screw up from a lower receiver? As parts for MGC Thompson is not that difficult to get, maybe I can help you out to find something.

Let me know as much as detail about your Thompson, with photo would help.

cheers,

S

Post by ljerr2

S-
Thanks for your offer to help. It is the version that the receiver pieces are screwed together from the bottom. The bolt has the extractor that has a visible screw through it instead of having the extractor pinned, like the latest models.
I think I will just sell it at a loss and not mess with it. If I don't sell it this week, I'll send or post a picture and go from there.
Thanks again for your help.

Post by Mark

Actually, the cuts that the receiver requires for the new extractor are small and they take little time with a "Dremel"to accomplish. I went through this conversion a few months ago on my early, open barreled, MGC Thompson.
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Post by figaro

You are correct, Mark, it would be less work than I had originally thought. It has taken a while for me to closely examine what actually has to be done to the Thompson to make the new bolt work (you did tell me in a previous thread it was a relatively painless job.)

The work needed appears to be a groove about 3 inches long by 6mm or so wide, maybe less than a 2mm deep, does this sound about right. (Beyond the first three inches (cocked position) the receiver seems wide enough to accomodate the new bolt without alteration.)

Might be an option for you LJ. Franky was easily the cheapest place I found for buying the new MGC bolt.
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Post by shazhib

OK, here is my findings. I think, there is a major differences on inner wall of upper receiver just behind an ejection port.

This photo shows the area where I am referring (with a screw driver), right side is old and new on left side.


The next photo shows a close up of the inner wall, as you can you see, it forms almost 90 degrees angle at/between side and top of the receiver


But this photo, old type, rather than been 90 degrees, it is kind of round connecting point


I think you need to mill a little bit to have 90 degrees angle the inner wall of old type to make new type bolt fits.

The next photo show a differences between old and new type from a top of upper receiver. The right one in faded color is old type, 2 holls just beside bolt top rail is where you screw from a top.


And the last photo is a differences of the bolts. The one with large screw is old type


Hope this will help, don't know how far you are able to understand my explanation, just for your info.

Thanks,

Post by ljerr2

Just an update for anyone that may be curious. I looked more closely at the receiver and the bolt on this "Collectors Armoury" model. The extractor isn't really even an extractor. It is just a piece of flat stock that is meant to resemble the older bolt extractor. The good news is that I can see that the upper receiver is already at 90 degrees, so no milling or Dremel tool is needed to fit a "current" type of Tommy bolt assembly.
If anyone else encounters one of these models, and I would think it would be the same, all you really need is a bolt assembly and chamber. As far as minor details, it also needs a screw to secure the chamber and the threads tapped into the hole that the chamber screw goes into.
Thanks for everyone's input - and a big thanks to Shazhib for the pictures and all.

Post by figaro

You may have a new style receiver on your gun but the 4 or 5 collectors armory imports I've seen all needed to be worked on before fitting the new bolt.
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Post by ljerr2

Figaro,
That's a good point and I shouldn't assume that they are all the same. I have had several of the "same" models that had minor variations in parts, etc. It is very likely that they could have used different recievers, depending on the time of import.

Post by figaro

I tried mine again, after reading this thread just to make sure, no joy.
I had to buy a new drum magazine from Franky, as the old one's were often sold by collectors armory as hollow shells, no internals.
Unfortunately the new mag was broken on a shoot, so I'm just not having any luck at updating this toy.
Sounds like yours is coming together well, which is good.
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