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Old 12-17-2009, 1:09 PM
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ar15barrels ar15barrels is offline
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Originally Posted by JF99 View Post
Randall, thanks again. I tightened down the shellplate bolt and the toolhead clamp bolts, then snugged down the support dies, locked them and set up and locked in the trim die headspace. Didn't even try to add the trimmer motor or vacuum line yet.

On my RCBS precision mic, the initial shells were showing shoulder bump of -.004", right where I wanted them. But when I ran 40 more through the system, the variance is about .007" (from +.001 to -.006).

Not sure what I'm doing wrong. Called Dillon and they agreed with your estimate that the system should be capable of .003" variance.


Different brass types will react differently to sizing.
This is due to variations in brass hardness.

Sort some cases by headstamp and size 4-5 of each type at one die setting, then measure them.
See how consistent they are within the same type vs within the whole mixed batch.

If you are running mixed types like me, just size them all so that even the longest cases are getting sized enough and don't worry about the short ones.
Randall Rausch

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