Brass neck getting thicker.

284 Win.

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Jun 2, 2010
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Hello everyone,
I have a 6mm Remington that I am using Winchester brass with and after 2 reloads the brass necks have gotten thicker. The necks have'nt been turned and to me it's not a donut at the neck and should juction. It's 1/3 of the neck thicker starting at the neck shoulder juction and up. I purchased a Pin gage set and .243 pin goes 2/3 down the neck and stops. I have to use a .241 Pin gage to go past the neck and shoulder area. I understand the brass flowing to the neck area but what can I do to stop this from happening. I was thinking of trying out some 7x57 Norma brass and just necking down.
Thanks Anthony
 
Have you measured the neck thickness?
A pin gage doesn't do that. You need a neck mic, or deep seat a bullet so that it's bearing is into the neck shoulder junction, and outside measure the neck.

And let me guess, you're FL sizing the necks, right?
 
FL resizing~yes.
Measuring the necks. I did at first and was going to turn the brass neck to clean up but there's .001~.0015 diff. from side to side and I didn't want to turn that much off.
 
What do you guys think of neck sizing then expanding then neck turning and just let the neck turner turn the thickin area off.
Anthony
 
What you have here is normal with FL sized -unturned necks.
Reloading 101; Brass tapers in thickness from the webs all the way to the mouths.
That means neck brass nearest the shoulders is thicker than neck brass nearest the mouths.
When you FL sized the necks, you pushed the entire neck(thick and thin) inward, and for no good reason. Now, the neck ODs are somewhat uniform throughout their lengths, at the expense of tapering neck IDs(which will increase tension).

neck sizing then expanding then neck turning and just let the neck turner turn the thickin area off
It's actually a little late for that as the necks have taken a set by the FL sizing of them. Best to do it (expanding only, and to the turning mandrel) when the brass is in new form, and it's springback is still uniform full length of the necks.
You could run a reamer in them crooked holes, but this will likely create permanent runout.
You could try re-expansion & turning.
You might decide that it's not a problem worth pursuing, based on your seating depths.
Or, just start over with new brass and a better plan.
 
Thanks alot Mikecr.
On my .284 Winchester I have noticed the neck being tapered but I haven't had any problem there at all. I neck turn the Laupa brass when it was new and the bullet is seated WAYYY out to stay out of the neck shoulder juction and I only have like .001 neck tesion on a loaded round.
The 6mm Remington Is Winchester brass and it"s not neck turned and YES the 87 Grain bullet is out to the lands loaded and is seated in the thickin brass area casing me problems.
Is it normal for you to neck turn brass again later down the road to take taper out. It just seams cheaper than to try to buy a Wilson inside neck reamer for every caliber you shoot.
Anthony
 
No, I only turn necks once.
But, I don't FL size.

With a lot of/typical FL sizing, you move thicker body brass upward into what was thin. Web brass rolls up the body, into shoulders. Shoulder brass rolls into necks. Neck brass rolls up to mouths. And soon it's time to trim away all the brass you move.
Donuts form, case weight drops/capacity goes up, ALL springback changes(somewhat countering capacity increase), shoulder bumping settings change, and necks(turned or not) get thicker.
This is why it's better to stick with a minimal sizing plan. I don't have any of these issues.

What that means is stop FL sizing necks. There is no good gained in this -only bad. It means have a custom body-bushing die made from your fireformed brass.
You can get this from many die makers. I use JLC Precision and couldn't be happier. His custom dies are not expensive at all.
Use Sinclair's expander die & mandrel for neck expansion prior to bullet seating.

If you turn necks, run rational pressure loads(~3kfps w/105gr bullets), use a custom body-bushing die, and expander mandrel, you won't be back here with issues mentioned so far.
You won't have to ream(ever) or turn necks beyond initial preps(your choice there). You don't HAVE to turn necks at all, if clearance allows.
 
So will a Wilson in line bushing neck die work? Neck size only and expand the neck with a expander mandrel.
Do you expand the neck for a more consistant neck tension with out having to neck turn.? More like pushing the little unconsistant ti the out side of the neck?
Anthony
 
So will a Wilson in line bushing neck die work?
Yes, this is what I use, followed by shoulder bumping with a JLC(bushing removed), followed by neck expansion with the Sinclair.
I do everything seperate preferring each action handled by the best tool for it.
It's low probability(for me) in getting it all perfect in one single die even with a Harrell press.

Do you expand the neck for a more consistant neck tension with out having to neck turn.? More like pushing the little unconsistant to the out side of the neck?
Yes, turned necks or not the last action should always be expansion, and it is either way. When you seat bullets you're upsizing necks. It is springback from this that holds bullets(tension). But if the ID is crooked, it's difficult to seat bullets straight, given that free bullets are not rigidly forcing thickness variance outward.
The expander in most resizing dies is again floating, and causes issues for most people.
The Sinclair expander mandrel is rigid and sized right to move thickness variance outward away from free bullet seating interference. It also leaves plenty of bullet grip, even with partial neck sizing(I size ~1/2cal of neck length).
I couldn't tell you why it works better than floating die expanders, but I know it does, and it immediately reduces loaded runout as measured off bullet noses.

Remember what I said about rational pressures though. If you crank the load up for some sort of upper-upper node,, well, you'll be forced to FL size with that.
Most LR cartridges hold a rational node somewhere around 2900 to 3000fps with heavy per cal Hi-BC bullets. There is typically an even more accurate lower node down at ~2700-2800fps. If you push it to a ~3100-3200fps node, forget the Wilson. Your brass won't even fit in it.
The 284Win is a good design. Go with the mid node and the only body sizing needed will be shoulder bumping beginning about the 4th cycle and every time afterwards.
 
Thanks again Mike,
.284 Win is running 2850 FPS. So that seams to be in the right spot.The 6mm Remington is what making me pull my hair out.
Anthony
 
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