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Re: Runnout

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06 January 2004, 17:31
muck
Re: Runnout
I'd start with quality NEW brass.
Sorted for consistancy in weight and neck thickness. You can also check for concentricity.
Then I'd follow the above posters advice.

A cheap solution to some of the runout can be as simple as changing your bullet seating technique. Most all of us place the bullet in the case neck with care then carefully raise the ram to push the case and bullet up into the seater die/stem until the bullet is seated. Then withdraw the cartridge. Done.

New technique: 1. carefuly place the bullet in the case neck.
2. raise the ram PARTLY, lower the ram a bit, rotate the cartridge 1/4 turn (this does not have to be precise). Raise the ram again Partially! Repeate the 1/4 turn until the bullet is incrementally seated.

You may be surprized how well this technique can work!

just my thoughts
muck
08 January 2004, 12:18
John Frazer
Quote:


A cheap solution to some of the runout can be as simple as changing your bullet seating technique.



I've tried this and it never seemed to change anything for me. Maybe I didn't do it right.

What I have found is that some bullets will just seat straighter than others. I believe it has to do with the shape of the seater stem.

I did 100 rounds for my .280 Rem. recently. Same lot of brass, same dies, same press; half with 139 Hornady SPs and half with 140 Partitions. About 20% of the Nosler bullets had more than .005" runout (measured about .1" above the case mouth). ALL of the 139 Hornady bullets had .005" or less, with probably 80% at .003" or less.

I've got an experiment in mind. One of these days, I'll swap seater stems -- use a .30-06 or .270 stem in the .280 die, do a bunch with the same bullet and see if the stem makes a difference. My hypothesis is that a smaller-caliber seater stem will grab the bullet straighter, earlier in the push.
08 January 2004, 13:28
Clark
It won't do any good to seat the bullets properly in a case with a bent neck.

The expander ball changing the neck diameter while pulling is the big culprit.


Once the big culprit is out of the way, then better seaters or better seating technique may improve things, a little.

Once the brass has been sized and expander balled at the same time, it may be too far gone to fix with just resizing without the expander ball. It may require firing, or epanding up to the next caliber and then resizing without the expander ball.

The problem with bent brass is that just bending it staight is not enough. It springs back .002", and so a bent neck will not be fixed by holding it straight. It must be over corrected.
08 January 2004, 23:02
jsr
It could be as easy as polishing your expander and making sure you'r getting suficient lube in the case neck,a Q-Tip will do it.
Jeff
09 January 2004, 00:22
mho
Great input you are getting above. The only thing I might add, is that for a surprisngly low price, the Lee Collet dies offer neck sizing with runout approaching or improving what can be had with a Redding Competition Neck Bushing die. Look for threads on this forum and see how many people have switched to the Collet die - with expensive bushing dies collecting dust in their drawers. PLUS, the collet die does not require cases to be lubed! The bushing dies are obviously still the better option if you want to be able to control your neck tension.
FWIW - mike