Needle Bearings On The End of the Spring?

[TonyL]

I did try it, and it does "work", but I couldn't detect any advantage over just a couple of hard steel slip washers and a dab of moly... on the downside however, their physical constraint mean they are tricky to fit to many smaller clylinder bore guns, plus there are the concerns about long term reliability.

And spring room .

I experimented with thrust bearings about 8 or so years ago.
I never really noticed an improvement over my usual setups.

If anything, as Nick says above, they pinch crucial spring room, so I stopped using them.

Yes. Excellent points.