The Sedgley 1911 barrel insert was a conversion unit that allowed the M1911 pistol to be converted easily into a single shot 22LR pistol for training purposes.
Once inserted into the M1911 barrel and aligned with the barrel hood. The sleeve would be precisely lined up to allow for the standard M1911 hammer to strike the 22LR rimfire cartridge and the extractor to remove the .22 long rifle casing.
Early units observed with serial numbers less than 1,000 were often inserts, while observed units above 1,000 came inserted already and pressed into a barrel.
Serial number 1174 is a later pressed in type. It has the no visible roll marks and has the serial number stamped by the breech of the barrel.