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Posted: 12/21/2012 12:30:05 PM EDT
| New to bottleneck reloading: My sizing checks .002" less than max on a case gage (shoulder to rim). My once fired check .001" less than max. (all same brass lot) I used dial vernier to determine measurements. Getting good groups, no doubles or any problems. Should I set my shoulder back a tad more? Thanks for your help!! BTW: RRA Wylde chambers (two new uppers) .223. |
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I hope you're using some kind of comparator. Because if you aren't, your measurements are in question. You need something that will read from the datum point to the base on the case.
This is what I use. http://www.midwayusa.com/product/479704/hornady-lock-n-load-headspace-gage-5-bushing-set-with-comparator |
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I have been using http://www.larrywillis.com with great success. |
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AR15's and for that matter any other semi-auto needs at least .003" haedspace clearance as a matter of safety and function. The "goal" should be .004" clearance. A .003" to .005" span is perfectly acceptable.
This allows for dirt and fouling as well as reduces the chance of a slam fire. |
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Quoted:
I hope you're using some kind of comparator. Because if you aren't, your measurements are in question. You need something that will read from the datum point to the base on the case. This is what I use. http://www.midwayusa.com/product/479704/hornady-lock-n-load-headspace-gage-5-bushing-set-with-comparator Datum point - is that not the shoulder as a whole or is it a specific point on the shoulder? IMHO I thought the case forward movement in the chamber was controled by the entire case shoulder. Your help is greatly appreciated!! By measuring the recessed depths of the sized and fired cases in a case gage(i. e. comparator), and subtracting the difference, I was thinking (maybe not correctly) that this would accomplish the desired measurement? I used the depth rod on the vernier caliper. |
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