Is a New Service 45 Colt pat oct 5 1926 chambered for the 45 Long Colt?
The "New Service 45 Colt" marking can either mean 45 Long Colt or 45 ACP, although the latter have a shorter cylinder and are extremely rare. Any gunsmith can verify the chamber length. There is no such thing as a 45 long colt it's a 45 colt . The 45 colt ACP is for a auto pistol . If your colt uses 45 APC it will need moon clips. But on the other hand they have a rimmed 45 APC now where you don't need moon clips. Take it to a Gunsmith. Unless the barrel is marked '.45 ACP' or '45 Auto Rim,' it's chambered for the standard .45 Colt cartridge. The mark will be '.45 Colt Ctg' or something very similar. Post-1917 New Service Colts factory-chambered for .45 ACP are rare, but certain 'shadetree gunsmiths' may have altered the chambering. That would involve changing the cylinder stop, the pawl, and the cylinder. TexasCharley -- Correct Markings -- If you have the 1926 patent date, you have a late commercial New Service. As mentioned above, chambering in .45 ACP was rare that late but barrel markings would be the same as the Commercial 1917: .45 AUTO. CTGE. If your gun is marked on the left side of the barrel: .45 COLT, then that is what it is chambered for unless it has been altered (although FAR more .45 ACP revolvers were altered than the other way around). Any gunsmith can mike the chamber and tell immediately. firstname.lastname@example.org