Case neck run out high

[victorcharlie]

After neck sizing my twice fired 30.06 cases I checked the run out on 50 rounds.  About 20 have a neck run out of .002 or less.  Many of the rest have run out in the .005 to .008 with some going into the .010 range.  Bullet run out measured in the cartridges indicate the same condition.  The part of the neck not sized is concentric to .002 so the necks are pretty good when they come out of the rifle.

I use the case master spacer to adjust the neck sizing die with the ram up and then tighten the locking collar which is what I do with all my calibers.

If I full length resize it returns the run out to .002 or so.

I checked the run out on the stem and expander ball and it measures around .002 give or take a fraction of a tick.

So, I checked 50 rounds of .270 and all neck sized cases are less than .002 run out.

Then I checked many of my .243 which I neck size and again, the run out is .002 to .003. 

Going back to the 30.06, part of the cases neck size fine so the die is probably okay?

I guess the best thing for me to do is full length resize again, and measure the run out after firing again?

This is military brass with a 88 head stamp (western).  The rifle is a Remington 700 BDL with Leupold VXIII 3.5 X 10.  The load is 51.5 grains of Win 760, 150 grain sierra spitzer and a Remington 9 1/2 primer.  This load shows promise and is shooting 5 round groups right at an inch with several through the same hole.  While this is more than acceptable accuracy I’d love to get it to shoot a consistent ¾ inch 5 shot group.

Any ideas?

[stimpylu32]

VC

Try taking a few of the worst cases and annell the neck / shoulder area , then run them back in the die , you may have some harder spots in the brass that is pushing the neck to one side . just an idea .

stimpy

[stimpylu32]

Also check your neck thickness , you may have some that are thicker on one side than the other .

[PaulS]

You may want to check the shell holder, die alignment, and the relationship between the two. If your die is out of alignment then your problem will only get worse. A worn shell holder may exaggerate any wear or misalignment. Uneven case necks (thicker on one side) and hard spots are also things that should be checked. In addition check the bullet seating die for dirt or misalignment. Make sure that the chamfer is even on the case necks and the bullets enter smoothly. Try a different bullet seating die to see if it corrects the problem.

[Catfish]

What kind of dies are you using? You have a problem some where. I load on a 550 Dillon and crank out ammo at a pretty high rate at time and have never found ANY run out on any of the ammo loaded on it.

[victorcharlie]

I'm using an RCBS neck sizing die.

The shell holder is the same holder used for the .270 and the .243, so I don't think the shell holders the problem as I have less than .002 runout on the .270.

I shot 20 rounds yesterday afternoon.  The neck run out on the fired cases are in the .002 range.

As I already measured the expander ball and stem, that leaves the die........

I necked sized some once fired federal brass.....same thing........008 to .010 run out.......

I'm thinking I'm going to call RCBS and see what they think might be up......

[beemanbeme]

Try doing a partial F/L resize and see what happens to your run out.  just put a dime or flat washer on each side of your FL die between the lock nut and the top of the press and try a few.  You did say you weren't running your neck sizer all the way to the shoulder didn't you. 
That may help hold your case in alignment.

[victorcharlie]

This one has me stumped......

I stopped by and picked up another RCBS neck sizing die........That didn't change anything.....

I annealed 20 fired cases, and checked the run out on the necks.  All are .002 or less.

I screwed in the new die, and adjusted with washers set on top of the shell holder and pressed up against the die, ram at the top, and adjusted the locking nut......ran a piece of brass and run out is .008.

That leaves the press, shell holder, or the brass.......or, my adjustment......

I haven't tried a partial F/L resize yet.....but the F/L brings the case out with less than .002 runout......

 

[stimpylu32]

VC

I too am stumped on this one , can't see having 2 bad neck sizers but with the 270 and 243's coming out ok that lends me to think that its not the shell holder or the press .

I guess the next thing to do is take a couple of the cases and index them with a marker in the press so you have a set point then back the die out 1/4 turn and see if the runout is 90 from were you started .

stimpy

[victorcharlie]

VC

I too am stumped on this one , can't see having 2 bad neck sizers but with the 270 and 243's coming out ok that lends me to think that its not the shell holder or the press .

I guess the next thing to do is take a couple of the cases and index them with a marker in the press so you have a set point then back the die out 1/4 turn and see if the runout is 90 from were you started .

stimpy

That's a good Idea, I'll try that........

I'm also going to go back and remeasure my neck thickness.......I was thinking it might be the military brass, but I have the same problem when using federal brass....and only with the .06......