Define too much.
- Thread starter Pathkiller
- Start date
D
Deleted member 10043
Guest
I don't know.
Like, wearing out the bushing until it no longer sizes the brass down?
D
Deleted member 10043
Guest
No, like I thought I read somewhere the bushing will eventually cause a bulge at the neck juncture. I can't find it now. So, it is a non-issue.
D
Deleted member 10043
Guest
I found it.
You also don’t get the build-up of brass at the base of the neck, as can happen with bushing neck dies.
bulletin.accurateshooter.com
You also don’t get the build-up of brass at the base of the neck, as can happen with bushing neck dies.
Tips for Using LEE Collet Dies « Daily Bulletin
For those who prefer to neck-size their brass (rather than full-length-size), the LEE Collet Die is a popular, inexpensive option. It works by having collet tangs or fingers press the neck against a central mandrel. The benefit is that you get a very straight neck, which is sized consistently...
Ahhhhhh. So, yes, it will push material to the base of the neck, resulting in a slight outside donut.
My observation however is that it will only displace a certain amount, and then it will just reduce the diameter without pushing material. It doesn't seem that the neck material continues to thin out with every use until it's no longer there. I'm on 15 firings of Lapua 6.5CM brass ans neck thickness is still .00125-.0013".
What I have also observed, is that outside donut almost acts as a chamber seal, keeping blowback off the shoulders.
I purchased a Mighty Armory full length die recently to try to reduce the number of press pulls per cartridge, but I started getting shoulder sooting.
Research suggests a few things such as brass not annealed (I anneal every firing), or low power loads not expanding the brass fast enough. I'm running 42.5gr of H4350 behing 140 Berger Hybrids and they're running about 2850fps. I don't think it's a weak load.
I've tried the Might Armory die on once fired factory brass and seen the same shoulder sooting.
It doesn't seem to affect my precision/accuracy mind you, as there's no discernable difference. I verified over 25 shots today it maintains sub half MOA out to 300 yards, which seems to be the best this barrel can do for me, regardless of die configuration. I was hoping for better, like the previous barrel, but it certainly checks the, "good enough" box.
My next test will be on new or once fired factory brass in a different barrel. Perhaps it's a chamber issue.
If I still see shoulder sooting, I will turn the donut off of a few cases and load a few rounds with both methods. Maybe I'll get sooting on both, or neither. Or maybe the results will be the same. One step at a time. It's going to be a long winter anyway.
My observation however is that it will only displace a certain amount, and then it will just reduce the diameter without pushing material. It doesn't seem that the neck material continues to thin out with every use until it's no longer there. I'm on 15 firings of Lapua 6.5CM brass ans neck thickness is still .00125-.0013".
What I have also observed, is that outside donut almost acts as a chamber seal, keeping blowback off the shoulders.
I purchased a Mighty Armory full length die recently to try to reduce the number of press pulls per cartridge, but I started getting shoulder sooting.
Research suggests a few things such as brass not annealed (I anneal every firing), or low power loads not expanding the brass fast enough. I'm running 42.5gr of H4350 behing 140 Berger Hybrids and they're running about 2850fps. I don't think it's a weak load.
I've tried the Might Armory die on once fired factory brass and seen the same shoulder sooting.
It doesn't seem to affect my precision/accuracy mind you, as there's no discernable difference. I verified over 25 shots today it maintains sub half MOA out to 300 yards, which seems to be the best this barrel can do for me, regardless of die configuration. I was hoping for better, like the previous barrel, but it certainly checks the, "good enough" box.
My next test will be on new or once fired factory brass in a different barrel. Perhaps it's a chamber issue.
If I still see shoulder sooting, I will turn the donut off of a few cases and load a few rounds with both methods. Maybe I'll get sooting on both, or neither. Or maybe the results will be the same. One step at a time. It's going to be a long winter anyway.
That's why it's always best to load just a few rounds first to see if they are right. If "right" then load as many as you need for that round. I've been there.
D
Deleted member 10043
Guest
Did you even bother to read the whole thread?
Bushings don't push material down to create the donut, if I'm understanding what you're saying here Tokay444
The donut is caused by brass flowing forward from the shoulder into the neck. It has nothing to do with bushings.
If you run an expander mandrel through after neck sizing it will push the donut to the outside of the neck. (if there is one)
If you size the case with a bushing it pushes the donut to the inside of the neck. (if there is one)
Either way, the sizing method is not the source of the donut.
Even if there is a donut, it is only an issue if the bullet is seated into the donut, which can be cured by a longer throat... And if the neck is a point of constriction as a result of the donut when chambered. If you have a tight neck and turn your brass, then its something to keep an eye on. If you dont have a tight neck, then dont give it a thought.
If you do have a tight neck, you should use a sizing bushing as a go gage to test for resistance. Just select a bushing that is 0.001" smaller than the neck of a fired case and slide it over your loaded rounds. If it slides all the way to the shoulder without force, then you have no reason to be concerned.
If the bushing binds at some point, then you need to get creative. Tony Boyer would sand paper the tight ones until clear.
Why do you think that the brass is not flowing from the shoulder?
Because brass flows forward. Similar to why you still need to neck trim too. I guess 60k psi has a way of pulling material with it or something, idk why, I just observe.
Also, yall need to differentiate between a donut caused by the chamfer on a bushing and the actual donut that’s the thicker shoulder material migrating forward. The bushing donut doesn’t matter, the real one does.
I think that what you think is a donut is actually from the bushing not bottoming out all the way to the shoulder. Many bushing dies have a bushing height adjustment that allows you to size only part of the neck. I suspect that is what you think is a donut, but its not.
So the neck thickness is the same all the way to the shoulder but the diameter at the mouth is smaller and just above the shoulder, it is larger?
Sorry, don't agree. For 308 and 300 Win Mag I use Redding bushing dies and I get the bushing diameter as far as the bushing goes and the larger diameter near the shoulder - so far, so good we agree. However, if I do that then seat a bullet, the bullet shank hits the donut and I get erratic seating force. I can feel the bump. So I use a mandrel and graphite because the mandrel expands the donut and the combination of consistent neck diameter and graphite gives me moderate and consistent seating force and no bump at the donut.
If you shoot new brass or only once-fired, you probably can't feel or measure the donut. I shoot brass until it starts to come apart. With many-fired brass I can measure the donut with a tubing micrometer. I recently started to anneal all my 308 and 300 brass every firing so maybe I will get a different result. Time will tell.
If you fire a case enough times, the brass just above the web gets thin and eventually the case fails at that point - I have hundreds of cases like that. The brass that started out just above the web moved away and it went somewhere. My theory is, some of it moves toward the shoulder and eventually makes its way into the neck. I don't know why it doesn't go into the web. I don't know why it doesn't move just a little then stop. But something makes a donut and the mandrel makes that better.
Are you running a tight neck? If yes, then you have a problem to deal with. If no, then set the bushing so it does not go all the way to the shoulder.
A donut can technically exist and cause no problems for you whatsoever as long as you have clearance in the neck and you don't size the whole neck to the bottom. If you float the bushing maybe 0.025" or so you will not reduce the last bit where the donut is.
I would try to float the bushing over the second operation with the mandrel because that will likely contribute to runout. The only reason I would use the mandrel is if I was loading ammo for a different rifle than it was fired in.
As for annealing, that will contribute to the forward flow of brass, not prevent it. The softer brass will flow forward more than harder brass. (slightly)
There is no doubt that brass flows forward during firing, that's why we need to length trim.
For my competition guns I always order a chambering reamer that allows me to seat the base of the bullet ahead of the donut, just so I take the donut out of play. I always run tight necks and turn though, so for me it's something I need to be careful about.
Last edited:
I don't agree that the "brass flows forward during firing".
What happens to the brass when it's fired? It expands outward until it touches the chamber with equal pressure on all interior surfaces. When you measure the headspace, it's more not because of any "flow" but because the whole case was stretched outward toward form to the chamber's surface (that's why we fire form out brass, huh?). If you measure the case length of the fired brass, you'll find it hasn't really changed in length from what it was before it was fired.
When you size the brass, you're squishing it down to make the dimensions smaller. When you "squish" it down, the brass has to go somewhere and this is where you see the "flow" happening. The shoulder is pressed down to get the desired bump and the neck is reduced and the brass "flows" in the only direction it can go making the case longer and with some being pushed into the neck-shoulder junction from the case wall being squeezed (visualize squeezing an handful of soft clay). Length trimming is only needed after FL sizing or even neck sizing only. . .not before
If one has a custom chamber with the minimum amount of clearance needed so that there's only just enough springback to allow case extraction, one is not going to see any "flow" even with any sizing as sizing won't even be necessary. Just read some of what Virgil King has said and done along these lines.
Priorities
2019:
"dude i got with this hot chick this weekend, blah, blah"
Friends: "pics, or it didn't happen."
2020:
"dude, I got 4000 BR primers this weekend, blah, blah."
Friends: "Pics or it didn't happen."
I admire that you prefer to draw your own conclusions, that's great, I very much do the same, but in this case I think you should read up, perhaps outside this forum.
I'll give you something to chew on, and its the difference in the frequency of length trimming depending on the shoulder angle. That has nothing to do with how anyone neck sizes.
Compare for example a 308 to a 6x47 Lapua or any Ackley improve brass for that matter. Take a little time and explore those and you'll quickly find your answer.
Sharp shoulder angles need less length trimming than soft shoulder angles. You can take that to the bank.
Yet neck sized only brass still needs trimming.
So I found this video interesting regarding FL sizing... If you skip to about 30 minutes in... Speedy talks about pairing the sizing die to the chamber just as I have have been criticized for recommending in the past, but coming from Speedy you guys might believe it.
He talks about normal dies that over resize the brass causing it not to perform to its full potential. That's why they make custom FL dies to idealize the amount of side wall resizing.
Keep in mind this advice is for guys who would be disappointed with 3/8 MOA groups.
He talks about normal dies that over resize the brass causing it not to perform to its full potential. That's why they make custom FL dies to idealize the amount of side wall resizing.
Keep in mind this advice is for guys who would be disappointed with 3/8 MOA groups.
Last edited:
