donuts to go

[Alibiiv]

I shoot a LOT. I have a pair of 223 varmint rifles that I go through 1000 rounds each every year during chuck season. The barrels are 8 twist which allows me to use 75g ELDM bullets. Those long bullets have the base seated below the case-shoulder junction, well below the neck shoulder junction where donuts form. I've known about donuts but looked at them like we all look at cancer, it will happen to someone else. Rude awakening while reloading some of my Lapua brass and having the seating process hit a hard spot where none existed before. I got donuts.

So, I started investigating the little devils to see what to do about them. Ignore them, ream them out from the inside or turn necks slightly into the neck shoulder junction. Ignoring them does not seem to be an option although I did try to back off the depth that my neck bushings resize the neck and that seemed to minimize the donut bump while seating the bullet. Have not tried those at the range yet and don't know if I will need a slightly smaller bushing to compensate for less neck tension because a shorter amount of neck is sized down.

I do not own the tools to turn the necks or to ream the inside and I'm hoping that someone here with experience with one or both can chime in. The LE Wilson inside the neck reamer says to use their reamer on fired unsized cases. It makes me wonder how that will clean out much of the donut without also thinning the case neck from the mouth down to the junction.
Neck turning apparently uses a mandrel to force the donut to the outside of the neck and then the cutter is set to lightly turn down the neck slightly into the junction. That would certainly seem to get more of the offending bulge gone. (at least that's my understanding)

So, who here has actual experience and advice with successful donut removal? Thanks in advance.

I use a Sinclair mandrel die on cases that have been full-length resized without the expander plug. I then use the Mandrel die to set the neck tension, "then" turn the necks. The mandrel pushes the donut out and the neck turning removes any excess material that was moved due to the mandrel.

 

[ntsqd]

Look up Porter's Precision Products if you want a Neck Mandrel Die that uses those same precision gauge pins for the expander mandrels. Then trying a different size might cost $10 for the pin in a huge range of sizes and the shipping instead of $15 for just the pin in very limited sizes.

 

[Airedale56]

THIS is helpful reading:

Case Neck – Forster Products

www.forsterproducts.com

and leads to this:

Inside Archives

Neck Reamers Thick case necks can cause high chamber pressures and flyers. The Forster Neck Reamer mounts in the cutter of a Forster Case Trimmer in place of the pilot and removes the excess brass from the neck walls with tool-steel blades. The Neck Reamer is manufactured from high-grade...

www.forsterproducts.com

Which leads to this:

Standard Neck Reamers – Forster Products

Select a product according to diameter (in inches).

www.forsterproducts.com

None of the above is an endorsement by me of Forster products.To me, it explained the issue better than everybody arguing about it in the previous posts….no finger-pointing by me. (Edit to add: I may have gotten confused about the arguing in this post vs older posts that pop up in the similar threads suggestions at the bottom of the page. Some folks got a bit cranky with each other. My apologies if anyone took offense from my comment here.)

I've been reloading since 1972 and I guess I've been lucky.
Never had the plague of "donuts" in my bottleneck rifle cartridge cases. I both FL and Neck size and bushing neck size.

But I am not nor will ever be a bench rest or F Class or 2-mile competitor.

Carry on.

"Can't we all just get along?" - Rodney King, LA riots

 

[Idgunner]

Airedale56, If I've absorbed all of that it appears to verify my decision to purchase an inside the neck reamer. Except it also advocates for an external neck trimmer, which is not my intention to purchase at this time.
Maybe I've just become more sensitive to the feel of the bullet seating process. All I know is that after setting the neck bushing so that it sized the neck as close to the neck-shoulder junction as I could get it I felt pressures in the seating process that I've never felt before. The bullets that I'm using are ELDMs and the boat tale base actually sits near the shoulder-case junction so they have to slide right past the neck shoulder junction.
I anneal my brass after every firing and some of these cases have been reloaded quite a few times. I've read that annealing, which helps to eliminate the effects of work hardening the brass, can also lead to the formation of donuts. Someone on here may dispute that and I'm certainly no expert.
I guess I will know soon enough because the tools will be here in a reasonable amount of time and I will ream out the necks of my fired cases and see if the bullets seat as smooth as I think they should.
Thanks for your input.

 

[Airedale56]

Idgunner,
My post wasn't directed at you or your original post.
Sorry if it sounded that way.

I haven't experienced "donuts" and started trying to understand what everyone was referring to, so I did some research and shared what I found, hoping it helped others.

I have neck turned some .308s and .223s in the 80s and 90s while chasing accuracy on prairie dogs and targets. I've never inside neck-reamed a cartridge case.

I have found over the years that what one person calls something and what another person calls it varies.
Terminology matters, especially in the firearms reloading process.

I even learned a trendy new word to describe heavy bolt lift from a top end load. Some guy online started complaining about "clickers" with his reloads. Just heard it for the first time in the last year or so. Who knew?

Anyway good luck in pursuit of a solution to your issue. I hope my links helped.

Again, I apologize to all if I ground my gears a bit…

 

[zwak 19]

To form brass to a larger caliber, is it better to use the cow method or a mandrel to avoid making donuts?

 

[BrentM]

I have an outside neck turning tool from K&M. I've used it a bit but when I switched to a mandrel for expanding it ended the process of fighting donuts. The issue is that the mandrel does add a step in the reloading and high volume reloading is slowed down. I've not done the inside reamer as the outside turning worked fine for me. Simply just set the cutter to very lightly skim the upper neck and then cut to the shoulder. The benefit is more concentric neck thickness.

 

[Mikecr]

To form brass to a larger caliber, is it better to use the cow method or a mandrel to avoid making donuts?

Neither would make a difference.
You can't solve a problem without addressing the root cause of the problem.

All cases taper in thickness from webs to mouths. This is inherent to manufacture.
So brass near neck-shoulder junction is thicker than brass at the mouths. Brass in shoulders is thicker than necks, etc.
When you up-cal, you put what was shoulder brass into neck-shoulder junction.
The way to resolve this is to turn lower cal necks all the way to slightly into neck-shoulder junction, AND THEN upsize to higher cal.

From there, it's always our sizing that amplifies donut area thickness, and sizing & seating that brings it into play.

 

[VinceMule]

Mikiecr advice is accurate.

I neck turn slightly into the Neck shoulder junction on the parent case going up or down in my case forming. A nit picker would turn again at the desired fully formed caliber as there may be .0003 run out on the neck turned formed up/down case. The second neck turning would result in run out from .0000-.0001 as long as your method remained constant.

When I formed 6 and 22 PPC out of PMC 7.62x39 brass, I shoot warm loads where the accuracy node is. IN 10 or so firings, some of the brass would still form doughnuts. I had brass Rockwell tested, and over a lot number, there may be 6% variation in hardness, which explains why the soft brass would develop doughnuts.

Anyone who has ever owned a 220 Swift, knows about how necks thicken over firings, and brass flowing from the case body to the case neck where tapered neck thickness can drive you crazy when trying to achieve very high levels of accuracy.

Much of the difficulty on neck turning has been removed by companies that sell:

A. Expansion mandrel

B. Turning mandrel

With a set of their tools. Even a novice can achieve .0002 run out with the two above tools while turning necks with the neck turning tool chucked in a variable 1/2" drill(speed control wheel on the trigger). Old-style neck turners that only came with a neck-turning mandrel could achieve .0005 run out, which is still better than most new factory brass run out.

K&M makes a good set for a novice to dive into the neck-turning.

 

[Idgunner]

Idgunner,
My post wasn't directed at you or your original post.
Sorry if it sounded that way.

I haven't experienced "donuts" and started trying to understand what everyone was referring to, so I did some research and shared what I found, hoping it helped others.

I have neck turned some .308s and .223s in the 80s and 90s while chasing accuracy on prairie dogs and targets. I've never inside neck-reamed a cartridge case.

I have found over the years that what one person calls something and what another person calls it varies.
Terminology matters, especially in the firearms reloading process.

I even learned a trendy new word to describe heavy bolt lift from a top end load. Some guy online started complaining about "clickers" with his reloads. Just heard it for the first time in the last year or so. Who knew?

Anyway good luck in pursuit of a solution to your issue. I hope my links helped.

Again, I apologize to all if I ground my gears a bit…

No apology needed. I figured that you were contributing the discussion in a respectful way. The internet can lead us in all sorts of wild directions and it is up to us to sort out which direction we take. I've decided to try the inside neck reamer because of my experience sizing necks and seating bullets. That and some odd fliers that make absolutely no sense. I'm shooting at chucks regularly out to 450 yards and now quite often out to 750 yards. Small targets at long distances requires that a lot of i's and t's get dotted and crossed. I have two pictures on my cell phone of targets that show my hold on a 1/2 inch dot and then the subsequent group given that hold. The target was at 200 yards which is my zero. I will try to post them here later today.

 

[Idgunner]

No apology needed. I figured that you were contributing the discussion in a respectful way. The internet can lead us in all sorts of wild directions and it is up to us to sort out which direction we take. I've decided to try the inside neck reamer because of my experience sizing necks and seating bullets. That and some odd fliers that make absolutely no sense. I'm shooting at chucks regularly out to 450 yards and now quite often out to 750 yards. Small targets at long distances requires that a lot of i's and t's get dotted and crossed. I have two pictures on my cell phone of targets that show my hold on a 1/2 inch dot and then the subsequent group given that hold. The target was at 200 yards which is my zero. I will try to post them here later today.

Airedale56, here are the pictures. The first is a drawing of my reticle hold on the 1/2 inch dot and the second is the group with that hold.

 

[VinceMule]

idgunner, I like the benchrest targets, 200 and 300 in particular. Shoot at the 4 corners, then the tangents on the circle on the 4 quadrants. You can get a real fine hold using this method, the same as your method on the orange circle. I must have a tinge of color blindness, as I can not see the edges of the red circle pasters..

I took the 200 and 300 yd benchrest targets and had a printer make the squares red, easy to spot your bullet holes instead of black where the bullet holes can disappear.

 

[243winxb]

will ream out the necks of my fired cases

In the old days, the neck was sized/held in a die while reaming.
Lee even made a target model loader that reamed, while the neck was held. The brass was then ready to load. Neck tension was light, about .001"

Reaming a fired case neck, not in a die, would seem to depent on brass spring back?

Outside neck turning would be needed, as a final step?

Just how i see it.

 

[Mikecr]

I don't see how a neck ID could be set as correct for a reamer diameter.
This is addressed with neck turning.