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Post by bradshaw on Apr 4, 2019 14:51:23 GMT -5
The only way to know whether a compression ring, aka thread choke, disappears when the barrel is loosened in the frame is to measure BORE and GROOVE DIAMETER before and after removing barrel. If the compression ring disappears when barrel is removed, trim barrel shoulder appropriate amount to TIME threads. Once thread pitch is known (Threads Per Inch----TPI), cut may be calculated based on degrees of a circle (360-degrees) which must be removed to hand-tight 10 or 12-degrees BTDC.)
Measurement via * Pure lead slug and micrometer----measure groove diameter. * Pin gauge----measure bore diameter. * Hole micrometer----measure groove diameter. May in some instances be used to measure bore diameter. Note: prongs must match number of grooves. A 3-prong hole mike corresponds with 6-groove rifling, but not 5-groove, etc. David Bradshaw
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Post by Burnston on Apr 9, 2019 14:25:52 GMT -5
I appreciate all the participation on this topic. It seems the issue is beyond my skill level to deal with. The pistol is currently on its way to a highly qualified smith whose solution is forthcoming. I will update you all on any progress.
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