The Spring Cap for the WE 1911 pistol installs in the slide over the recoil spring. WE Part number 33, or WEM33
The recoil spring cap has a lip that can break off after extended use. If that lip breaks, all the recoil force is applied against the barrel bushing. You can usually see a broken or bent barrel bushing fairly easily by looking at the front of the slide on a WE 1911. If the barrel bushing is bent or broken, make sure the spring cap is also checked. If you replace the barrel bushing without replacing a broken spring cap, the new bushing won't last long.