Trickymissfit
Well-Known Member
...never mind the fact that the case head to body aren't perfectly square on virgin brass and you may be dealing with banana cases to a small degree even after firing in the perfect chamber due to uneven case wall thickness, all of which assumes your chamber and bolt face are true and concentric to begin with as you pointed out.
I think I'll stick with the HNL comparator to get a workable setting for my dies and then spot check just every now and then to be sure there hasn't been any meaningful drift.
One option might be to use your reamer to make a die which could sit neck down on a flat base and then use a flat/square ground disk on top of the case head to measure with an indcator. That might mitigate the effects of the ellusive centerline much like your Wilson seater doesn't have to be dead center under the arbor press. ...a simpler, home made version of the the Redding Instant Indicator. But, you don't fire your ammo in a die or in a Redding indicator. You fire it in a chamber made from a particular reamer as you pointed out.
It really comes down to what you want to accomplish. If you're out for speed/efficiency, then indicators are faster/easier for me than calipers and mics. But, I don't check HS on every case.
If you only want to be within a thou, then calipers are pretty easy to spot check.
If you want to go to tenths, then I suspect you need to reasses not only the measuring apparatus and technique, but the general behavior of brass (temperature, spring back, settling, work hardening, etc) as well as your process for sizing and staying within your desired tolerance which may or may not have a bearing on precision shooting.
-- richard
I did make some shell holders once out of 1" Thompson rod, to use in my Wilson trimmer. So i guess that would also work OK. I have a little gauge I made for checking case run out years and years ago. Don't use it much anymore, but it's great for checking a case for the banana. I fit all my cases to the chamber first. I personally see little benifit in getting it right down to a couple tenths, but I do try to work in a +/-.0005" window. I doubt that my dies are any better than that anyway.
gary