Recived a box of mixed shells from the wifes late uncle and one of them is marked 41 SDA. The bullet is a lead RN and measures .40 and its a semi rimmed case thats a little shorter than a 380 auto case,sample I have was loaded by Western.
Anyone know what kinda of pistol was chambered for it and its history.:::::::MV

Sounds as if you have a 41 Colt Short cartridge.
Case length .650,Head dia .408,Neck dia .404,
bullet dia .386 rim dia .435
It could be fired in any revolver chambered in
41 Long Colt,model 73 single action or model 1878
Thunderer double action revolver.It may have been chambered in some of their pocket pistols also.
WC

.41 Short Double Action . . . Colt round. There was an enormous variation in the .41 Short Colt depending on the ammo maker and the version. Basically, it is somewhat shorter and less powerful than the Long Colt. This is a rimmed, not semi-rimmed, round.