Editing Thompson submachine gun (section)

====Model 1927====
The Model 1927 was the open bolt semi-automatic version of the M1921. It was made by modifying an existing Model 1921, including replacing certain parts. The "Thompson Submachine Gun" inscription was machined over to replace it with "Thompson Semi-Automatic Carbine", and the "Model 1921" inscription was also machined over to replace it with "Model 1927." Although the Model 1927 was semi-automatic only, it was easily converted to fully automatic by installing a full-auto Model 1921 fire control group (internal parts). Most Model 1927s owned by police have been converted back to full-auto.{{sfn|Iannamico|2000|p=21}} The original Model 1927 is classified as a machine gun under the [[National Firearms Act]] of 1934 (a) by being "readily convertible" by swapping parts and (b) by a [[Open bolt#Legality|1982 BATF ruling]] making all open bolt semi-automatic firearms manufactured after the date of this ruling classified as machine guns.