RCBS vs Redding runout

[Brain]

Has anyone seen a marked difference between using RCBS and Redding dies in neck runout?

I am considering switching to Redding bushing style dies due to sizing induced runout when using RCBS. Prior to sizing, my cases are showing less than or equal to .001 neck runout. After sizing, it is in the .003 - .004 range consistently. I have tried removing the clip from the ram in order to let the shellholder float but it returned no improvement. I have also tried sizing very little at a time while rotating the case until the neck is fully sized with no improvement.

Yes, I'm a perfectionist but I understand limitations of equipment. It is however frustrating to have almost no runout prior to sizing and a lot afterwards.

[AJ Peacock]

Have you removed the sizing button from your die? That is likely where the runout is coming from. I remove mine when my brass is good enough (consistent neck thickness) to allow it. When I can't, I always polish it to a perfect finish and use plenty of Imperial sizing wax inside the necks. Also a smooth steady (not fast and not slow) extraction over the button seems to work best.

If you can't remove the button, make sure it is perfectly centered (the entire decapping assembly) in the die.

AJ

[Brain]

AJ,

Yes, I have removed the button in all of my dies. Forgot to mention that earlier.

[AJ Peacock]

If resizing is giving you runout with the buttons removed and the shellholder floating, I'd definitely blame the die.

One other thing to try.

1) loosen the lockring on your sizing die
2) put some up pressure on the die, by placing something between the shellholder and the bottom of the die (I use a small 1/4" shim with a hole through it)
3) while pushing up, lock you lockring.

This takes some of the slop out of the threads between the die and press and has been known to straighten things up a little.

AJ

ps: I'd get the Redding dies anyway

[Brain]

Ok, tried the upward pressure on the die while tightening the lock ring. No change in runout.

I guess it's finally time to break down and get the Redding dies...and I just missed the end of the 50% sale Roll-Yur-Own was having on Redding

Thanks for your input AJ!

[Ray]

Try one other thing before you buy. With the expander ball removed and if you have a universal shell holder on the press remove the snap ring that holds the shell holder in place. Resize a case and check run out. By doing this the shell holder and case can float which will allow the case to seek it own center into the die body. If this works then it is an alignment problem and/or possibly trash. You can just leave the snap ring out or clean it well. Let us know how it does. Good luck! Ray

[Brain]

Ray,

Thanks for the reply, but I mentioned in my first post that I had already tried it without success.