The FAL/Thompson 45acp conversion

Instructions for the do-it-yourself installer

   These are basic instructions that use common tools that most people have around the house. This is assuming you have already installed your barrel and converted your bolt or have a new para bolt. 

Click here for the barrel and bolt instructions.  


Basic Parts



Step 1

Test fit the front block assembly.

This part easily snaps apart from the rear block using just hand pressure. Next make sure the front lug is installed, now insert the adapter like it was a regular mag and try to insert the lug into the lug hole. Once the adapter is installed, press down from the top to make sure the adapter will not be pushed down during use.

It should easily fit into the lug hole, if it does not then try rotating the lug a half turn and retry.


It should now look like this, notice there is hardly a gap from the adapter to the receiver. This is a No-go fit. Notice the gap.


If you can not get a good tight fit between the adapter and receiver then use a file or sand paper and remove some material from the  corner of the adapter side plate. I have found this to be necessary for the Aluminum receivers.


Once you get a good fit between with the front adapter parts, remove it and move on to the next step.



Step 2

Test fit the rear block. On this part you want to make sure that you have a good contact between the original bolt stop and the bolt stop transfer assembly.

You will need to shorten the pin on the original bolt stop and you may need to shorten the top pin on the transfer assembly. You can check these by inserting the block into the mag well and pressing rearward on it. At the same time look at the pins from above and make sure the parts freely move.

The original bolt stop pin needs to be above the pin on the transfer assembly. The pic to the right show how we ground ours.

Make sure the original bolt stop pin does not touch the brass part, this will cause the parts to bind up.


Step 3

Now reassemble the complete adapter and insert it into the mag well. It may be tight in most receivers. It may not even want to fit into the Hesse and Century cast receivers. You will need to use a file to widen the mag well. Gunsmiths use a mill and skim off a little. Once the assembly is inserted all the way, use a block of wood and a hammer to tap it the rest of the way in, you will hear the original mag catch snap into place.  


Step 4

Testing, before you begin to blast away tumble weeds with your new 45acp carbine you need to do some testing.

First make sure the bolt clears the ejector, it should not touch it at all.  If it does, use a file or even sand paper to remove some material.

Next, test fit a magazine. Insert it, you may need to give it a good tap from the bottom to so it will snap in. If it will not snap in, then you will need to remove the mag catch and use a file or sand paper to remove some material from the top of the catch. Re-do until the mag seats nice and tight.

Once you get the mag in, make sure the bolt will not hit the feed lips, if they do then use a file to remove a very small amount from the feed lips so the bolt will not hit them. Usually around 1-3 millimeters.



Thompson mags.

There are only a couple scources for Thompson mags at this time. Below is a list of a couple. I have no idea what to expect in the way of quality or shipping times.

Forrest Co. 1-888-372-5968

Ohio Ordnance 1-440-285-3481

Tapco. 1-800-554-1445

What a Country 1-949-951-4610

Watch out for semi auto mags. The mag on the right is a semi auto mag, the rear hole has been turned into a oval shape. These are very difficult to use and need the adapter to be modified and a new mag catch used. Also semi Tommy mags are usually more expensive.
Mag quality. Generally any Thompson 20 or 30 rounder mag will work. However you will need to inspect the follower. A bad follower will cause many problems. Take the follower out and make sure the tabs on the bottom are not bent out of shape.