Firing Pin Stops, Springs and Firing Pins, etc for your 1911.
For a general guideline -when selecting a firing pin stop, you need to know if your pistol is a Series '70 or a Series '80.
A Series '70 pistol will use either a HD-205 or a HD-206. The HD-205 is only for .45 ACP Government Model pistols, in the majority of manufacturers. The HD-206 is for all calibers in smaller 1911s and mid-size calibers in the Gov't Model. Example - 10mm Gov't, .45 ACP Defender, .38 Super Commander, Gov't, etc.
A Series '80 pistol will use either a HD-207 or a HD-208. The HD-207 is only for .45 ACP Government Model pistols, in the majority of manufacturers. The HD-208 is for all calibers in smaller 1911s and mid-size calibers in the Gov't Model. Example - 10mm Gov't, .45 ACP Defender, .38 Super Commander, Gov't, etc.
There are variations from these guidelines, so the smart move is to compare your firing pin stop to the pictures in this section. The two key spots to check are the ejector clearance notch in the lower left corner and whether or no you have the Series '80 firing pin safety.
A Gov't Model notch does not come as close to the hole for the firing pin as does the FPS for all other calibers & models.
Note - Firing pin stops are not drop in parts. They require fitting to the individual pistol. If the necessary techniques do not fall within your skill set or tooling capabilities, seek help from a professional gunsmith!