Case neck run out

ChetStafford

I bought an Rcbs case master measuring tool pretty handy little gadget.

I measured 75 cases and found most of them had .001 or less run out a few had .002 to .003 is this enough to worry about?

I do not do any competition but I do want to make the most accurate rounds I can

How would you go about getting these straightened out?

Any help will be apprieciated

JustC

were these measured after sizing or before?

ChetStafford

JustC,
These cases were already full length sized

most of them were less than one thousandth out of round
but about 4 were off by 2 to 3 thousandths

steve4102

Measuring neck runout will give you an idea of how well your dies are set-up, but in many cases it will not tell you much about the concentricity of a finished round. Ya see, you are measuring the outside of the brass and the bullet is seated on the inside of the brass. The only way the inside and outside will be equal in runout is if you have turned the necks so the brass thickness is even all the way around. It is not uncommon for brass to have very little neck runout and a whole bunch of "Bullet" runout and vise verse.

Seat some bullets and then check "Bullet" runout. Much more important than "Neck" runout. Try for as little bullet runout as possible. For my hunting rifles I like to keep bullet runout under .002, although many hunters will say .005 is max runout.

Tailgunner1954

If your after groups in the 1's (.010-.019" C-C) or smaller than ya, it's worth worring about.
If your after groups in th 3/4"-1 1/4" range than it's not something to worry about, because you/your rifle aren't good enough to see the differences.

The vast majority of shooters/rifles can't tell the difference between ammo that has .001 runout and that which has .020 runout.

steve4102

quote:Originally posted by Tailgunner1954


The vast majority of shooters/rifles can't tell the difference between ammo that has .001 runout and that which has .020 runout.


Maybe, Maybe not. I have three CZ rifles that will shoot sub MOA with just about anything I feed them. Runout is not an issue with these three rifles. I also have a Win M70 Featherweight in 6.5x55 that will shoot consistant 1 to 1 1/4 inch groups with minimal runout. If runout gets over .004 with this rifle my groups open up slightly, but I get frequent fliers out to about 3 inches. If runout is over .010 it starts to shoot patterns instead of groups. No runout, no fliers.

JustC

runout shows up as distance increases. a few .001's means very little,....I'll run with that in 600yd matches. I try for .001" but will use the .003" rounds as spotters in the sight-in period.

ChetStafford

JustC,
thanks for the information.

I checked some loaded rounds and most of them were .001 a couple were .002 I figure that will be just fine for what I am doing now