1921 vs 1928 thompson receiver

[benedw60]

Other then the engraving, is there anyother machined features that would let you know if a receiver is a 1921 vs 1928 or is the base geometry exactly the same for the two receivers?

[Adg105200]

Do you mean the difference between a Colt 921 and a Ww2 production 1928, or a Colt 21/28 Navy overstamp?

 

Dimensionally all of the 21 or 28 receivers are the same. It really comes down to finish and markings.

 

Andrew

Edited November 20, 2017 by Adg105200

[TD.]

Exactly the same on Colt manufactured receivers! It may be possible to tell the difference between a blank Colt's, Savage or Auto-Ordnance Bridgeport (AOB) receiver from the machine operations. But the receivers were manufactured from the same blueprint so theoretically should be the same.

[jim c 351]

All Colt 28 receivers began life as a Colt 21 receiver.

Perhaps you'd care to ask if there is any difference between a Colt receiver and a Savage and Bridgeport receiver.

Then again, maybe you wouldn't.

Jim, C

[Got Uzi]

Only difference I can think of (other than markings) would be the slot in the top as some were square in the early numbers but later on all were round.