Some members who do a lot of barrel swapping have noticed that the sides of the barrel extension ['receiver'] can be misaligned, or twisted, or even bent in such a way that the extension drags on the frame, especially in the frame 'ears' area. This can be checked by a couple of spirit levels across the extension sides; careful measurement of the gap between the sides; and a ground parallel held to the extension sides, to see if there are any gaps when held to a light. A ground drill rod placed in the bore will also show up any misalignment when used in conjunction with the spirit levels.

Any small faults can usually be remedied with a combination of lapping compounds to get a smooth drag-free action. Severe misalignment calls for more drastic action, such as careful bending of affected parts.

As always, hope for the best and be prepared for the worst. :thumbup:

I'll chime in with Marc and Rich here. Testing without springs will reveal a serious misalignment if it's there. Whether the forks are bowed, twisted, splayed apart, pinched together, or parallel but offset will make a difference. All parts of a spring-less action should move like buttah!