Welcome to the forum.

Measure the barrel-to-cylinder gap with the cylinder held to the rear (a set of automotive feeler gauges work well). Then make the same measurement with the cylinder held in its forward position. The difference is the endshake. 0.001"-0.002" endshake is acceptable. Get whatever combination of bearings that will reduce your endshake to the specifications. Remember that some small amount of endshake is necessary for the gun to function reliably.


Buck