jcelect,

Excessive headspace and endshake can be corrected by replacing and re-fitting a new yoke, by stretching the yoke barrel or, more commonly, by using shims to return the yoke barrel to the correct length. When this is done, the cylinder is moved back to an "in spec" condition with respect to headspace, and the b/c gap is opened the equivalent amount. So if the cylinder is moved back .004", the barrel cylinder gap will also grow wider by that amount.

If the b/c gap gets too large, or over .012" according to the current factory spec, the barrel can be set back one additional turn, or approx .028", and the b/c spec re-set by re-facing the resulting longer barrel extension, and re-cutting the forcing cone if necessary. Of course, after the barrel is set back, adjustment of the extractor rod and front locking bolt interface is also required, which can be accomplished by shortening the extractor rod collar and tweaking the center pin's OAL.

Always remember, if the headspace and b/c gap are within specifications, end shake is a "non-issue". Some end shake is not only normal but necessary, and this gauge or space is, in fact, built into the cylinder assembly to allow for proper operation (opening and closing), the proper, unrestricted rotation of the cylinder, and for the assembly to accommodate dirt and lubricants.

Carter

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Ret. LE, FA Instr, S&W Armorer