I just finished relining a 22 Long and modified the carrier to take a 22LR. Got it back together, but now there is considerable bolt slop, so much I am concerned about headspace and firing pin position. There is about a mm of fore and aft; but more worrisome, there is about a mm of up and down which seems more pronounced on the right side. This up-and-down goes away when the hammer is forward on the firing pin. As best I can tell, when the hammer is fully forward, that depresses the carrier which allows the bolt to sit all the way down and stay there. At other times the bolt is riding on the carrier spring arm and that pushes it upward.

Where should I start? Maybe tig the cam surfaces? Squeeze the action? tig the bolt shoulders?

Well I tigged up the round projection that on the action bar that rides in the cam, it had a pretty nice flat spot, and that improved things a lot. Test fired 3x, all looks normal.