Hello there,
I have one LAW folding adapter and decided to move it from my 5.56 pistol to my 9mm pistol.
I don't have a picture of the un-modified bolt carrier extension, but the first thing I did was cut the expanding fingers off that go into the rear of the standard 5.56 carrier. I faced it off in my little lathe, and drilled the threaded hole out to 1/4".
Next, I removed the pin that holds the weight inside the carrier..........
Then I drilled and tapped the weight for 1/4 UNF.
Put the weight and pin back into the rear of the carrier.
Used some locktite and screwed the bolt carrier extension in place.
Test fired about 10 rounds and all seems to be good.
There is nothing but friction holding the extension from turning, but that is the way it works on the 5.56 carrier too. I will check it now and then for rotation, but I don't think I will have any trouble.
The whole process took me about 20 minutes. Without the little lathe, it would obviously be a little more work.