Please explain how the Thompson was converted to semi-auto only. Rules for conversion of an MG to semi-auto or manufacture of a semi-auto MG in the US are vry specific and strict. Would be interesting to know if you can take the time. Thanks.
I have seen a semi auto "permanent" modification, trust me is better to see it deactivated rather than "castrated" lol. of course first step is removal of the selector, second they cut the bolt on the bottom 80% of its lenght and some of the bolt height (to remove its channels) and insert a moving rod that acts on the sear, then the actuator is again modified, they mill the spring channel in order to insert another movable rod that strikes on the receiver, in this process they also mill a small portion of the b lock (in the middle, making it very prone to breaking).
Lastly, they insert one spring for each horrible device that so you end with three different springs, and a small plate to be inserted at the back. The system is so ugly and complicated, that the author would still deserve a medal for designing it.
Of course if one is able to swap parts, in this case everything except upper, you end up again with a mg
Edited by indochinavet, 15 May 2018 - 03:05 AM.