Are they Class 3 exempt, or have they been modified to only shoot semi-auto?
Even the full auto often became semi-auto since they would jam like Grand Funk Railroad.
I just helped a guy toward paying the fee ($200?) so his was full auto, I’ve never heard of a semi-auto M-3.
FYI, the plant here also made those `one-shot’ pressed steel, use a gun, get a gun, .45 pistols provided to the French resistance.