just use your verniers to check your neck thickness
be aware though that used cases usually are thinner at the case mouth than at the base of the neck
if you put the vernier jaws half way into the neck you should get a good idea of what it is
check this at 4 points and only consider them if they are very close to the same
if you add up the neck wall thickness x 2, add the bullet diameter you will have the loaded round neck thickness without neck tension
then measure one of your loaded rounds and take that amount off the above figure and that is the neck tension you are currently using
I like around 2 thou but no more than 3 thou, bullet release is IMO very important
measuring a fired neck gives an indication of your neck clearance in the chamber
I like around 3 thou, but have tighter in tight chambered rifles, around 5 thou clearance can be normal for factory chambers
using lee collet dies or bushing dies keeps the case in a straight line with the bore because they don't size a small part of the base of the neck
that makes it not as bad to have a heap of neck clearance in the chamber
rcbs do a concentricity gauge that does neck thickness but I don't think it is very accurate because it does not use a pilot, probably better with verniers
www.youtube.com/watch?v=7KbOCN7rEvUwhen sorting out cases by volume I would expect 1/2 a grain to be exceptable but other opinions may differ
everyone make a curry different
love that saying, thanks Daddybang
looking through the flame is right but you will not see the changes properly till you pull the case away
then you will see how far down the case the heat has gone straight away and you will see the changes
you could use a bbq flame or a gas stove to do it, if the missus is out for the day
like I said its a trial and error thing, get your counting and rhythm happening and you'll be right
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