AJ Peacock
Well-Known Member
You are correct on the second 'expander ball', it's just to hold the primer punch pin when resizing without an expander ball. I rarely use an expander ball with those die sets.
AJ
AJ
Neck Concentricity Help
- Thread starter esshup
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esshup
Well-Known Member
Thanks AJ. I think I've got the problem solved. I sized 20 new pieces of brass and the runout is between .0005" and .0015"
AJ Peacock
Well-Known Member
Is that after the bullet has been seated? If not, you will probably gain a little bit during seating, due to neck wall thickness variances.
Either way, I'm sure you have the problem on the run now.
AJ
esshup
Well-Known Member
AJ:
That's just the case. I do have an unused neck turner sitting here........ If the runout gets much worse after seating the bullets, I might learn how to whittle a bit of brass off of the thick side of the neck! (and a miniscule amount off of the thin side as well, I guess
)
Thanks!
That's just the case. I do have an unused neck turner sitting here........ If the runout gets much worse after seating the bullets, I might learn how to whittle a bit of brass off of the thick side of the neck! (and a miniscule amount off of the thin side as well, I guess
)Thanks!
AJ Peacock
Well-Known Member
One trick I do with the bushing dies. I let the bushing float a little, instead of locking it down solid, I also don't resize the entire neck (only 2/3 - 3/4 or so). That way, the un-resized portion of the neck will help center the cartridge in the chamber (assuming a previously fired brass and not a new brass).
All that said, I've shot some pretty good groups with new brass that was not even sized.
AJ
All that said, I've shot some pretty good groups with new brass that was not even sized.
AJ
esshup
Well-Known Member
Thanks AJ. I only have 6 rounds of fired brass for this .257 Wby, but I purchased 100 pc of new Norma Brass. Unfortunately, I ran about 1/2 of those thru a neck sizer w/expander ball that made up to .007" run-out. (Stupid rookie mistake thinking that the dies would be just fine so I didn't buy a concentric indicator until 2 weeks ago. ) So, I'm now stuck with trying to get them back concentric. I'd really like to do that without having to run 50 to 60 bullets down the tube!
) So, I'm now stuck with trying to get them back concentric. I'd really like to do that without having to run 50 to 60 bullets down the tube!boomtube
Well-Known Member
"If I leave the expander ball in the die, I get .004+" run-out. If I take the ball out, the run-out is .001" to .0015"."
Obviously, the problem lies with the way you are expanding, nothing to do with the sizer body itself.
Actually, the problem you have is very normal with common dies, it's due to the way we have to pull a expander back through the sized necks. All necks have a softer or thinner side that side expands more, and that distorts them. No amount of tightening or loosening or turning durning sizing will change it. To avoid bending necks we have to do something entirely different.
First choice is the Lee Collet Neck Sizer die. There is NO expander in it, just a bullet-diameter mandrel which the necks are squeezed against. Using it is different so there is a learning curve and if you aren't willing to take the time and effort to do that it is the wrong choice. But it WILL NOT distort necks as conventional expander type dies do.
Second choice is to take the expander ball out of your die, toss it and size normally. Then use a Lyman "M" expander die. It pushes IN rather than out, so the neck is well supported by the shoulder during expansion. There is much less tendency for the necks to bend toward the soft side with the M die.
With either method, it is helpful to lightly skim turn the necks a little, maybe as much as 60-80% of the circumference of the neck, just to even up the thickness.
For light neck cuts for factory rifle ammo, serious and expensive BR grade neck turners are uncalled for. If you have a case trimmer from Lyman, Forster or RCBS you can get simple attachments to turn necks from those makers.
As an excellant alternative, I'd suggest the Forster "HOT 100" hand held turner. It's inexpensive, has a carbide bit and is "micro" adjustable, few others are any better and all others cost more. Some cost a LOT more! Midway has them. Or they did.
Using these methods, I have cut the run-out of my loaded ammo to about one third of what it was before, on average. And the percentage of my cartridges with near zero run-out is much greater than before!
Obviously, the problem lies with the way you are expanding, nothing to do with the sizer body itself.
Actually, the problem you have is very normal with common dies, it's due to the way we have to pull a expander back through the sized necks. All necks have a softer or thinner side that side expands more, and that distorts them. No amount of tightening or loosening or turning durning sizing will change it. To avoid bending necks we have to do something entirely different.
First choice is the Lee Collet Neck Sizer die. There is NO expander in it, just a bullet-diameter mandrel which the necks are squeezed against. Using it is different so there is a learning curve and if you aren't willing to take the time and effort to do that it is the wrong choice. But it WILL NOT distort necks as conventional expander type dies do.
Second choice is to take the expander ball out of your die, toss it and size normally. Then use a Lyman "M" expander die. It pushes IN rather than out, so the neck is well supported by the shoulder during expansion. There is much less tendency for the necks to bend toward the soft side with the M die.
With either method, it is helpful to lightly skim turn the necks a little, maybe as much as 60-80% of the circumference of the neck, just to even up the thickness.
For light neck cuts for factory rifle ammo, serious and expensive BR grade neck turners are uncalled for. If you have a case trimmer from Lyman, Forster or RCBS you can get simple attachments to turn necks from those makers.
As an excellant alternative, I'd suggest the Forster "HOT 100" hand held turner. It's inexpensive, has a carbide bit and is "micro" adjustable, few others are any better and all others cost more. Some cost a LOT more! Midway has them. Or they did.
Using these methods, I have cut the run-out of my loaded ammo to about one third of what it was before, on average. And the percentage of my cartridges with near zero run-out is much greater than before!
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