donuts to go

[Idgunner]

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.

 

[Barrelnut]

I've used a RCBS inside neck reamer. Use it after you have sized and expanded the neck. It goes in with a slight tight fit and will cut the donut out. Just need some sort of chuck to hold it. I used one of those chuck tools that comes with a hand tap set. It's only a 12 buck tool.
https://www.rcbs.com/case-processing/ream/pilot/neck-reamers/535.html

 

[VinceMule]

Quote:

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.

I don't think that you fully understand the problem. The doughnut is right at the shoulder-neck junction in the case. As the bullet goes through the doughnut, it puts a squeeze on the bullet, how much varies from doughnut case to the next doughnut case. Pressure spikes for sure. How much the pressure spikes is anyone's guess. How much damage the doughnut does to the bullet is another guess, as it may scrape off part of the jacket making it a smaller diameter.

How you deal with doughnuts is a function of the money you want to spend. K&M makes a carbide mandrel with a cutter on the end in 22 caliber. How you hold the case for the operation and how precise you want to be is another question.

In the meantime, I would suggest that you insert a bullet into each case after being fired. There may be enough clearance for you to slip a bullet down past the shoulder-neck junction. As you find a case with doughnuts, cull them aside and deal with them later as you figure out your style of dealing with this issue. If you do not have the clearance after firing to slip a bullet down the neck, then McMaster Carr sells pin gauges you can use.

 

[K.E.C.]

Why don't you clean the donut out?
Get a old short cleaning rod , bronze and nylon brushes. CLR works very well.
Or any bore cleaner and scrub the chamber. Hope this helps.

OOPS, disregard. My Bad.

 

[338 dude]

I have a Wilson case trimmer for which I buy the inside neck reamer ,it will ream out the donuts on a fired case. Then when you use your die check your neck size you may have to change bushing size after this step.

 

[338 dude]

You can also get a neck expanding mandrel. This will help to give some clearance,

but not completely remove the doughnut.

 

[Lone Hunter]

Why don't you clean the donut out?
Get a old short cleaning rod , bronze and nylon brushes. CLR works very well.
Or any bore cleaner and scrub the chamber. Hope this helps.

I believe he is talking about the brass doughnuts that form inside the brass cartridge not the carbon ring in the barrel..

 

[VinceMule]

+1 First class set up on the Wilson!

Attach a variable 1/2" drill on the spindle after removing the knurled handle, run it around 80 rps. The variable speed drills with the speed control wheel on the trigger work the best.

 

[338 dude]

And if you have a micrometer adjustable neck sizing die do not size all the way to the donut I only size about 3/4 of my necks.

 

[Idgunner]

I don't think that you fully understand the problem. The doughnut is right at the shoulder-neck junction in the case. As the bullet goes through the doughnut, it puts a squeeze on the bullet, how much varies from doughnut case to the next doughnut case. Pressure spikes for sure. How much the pressure spikes is anyone's guess. How much damage the doughnut does to the bullet is another guess, as it may scrape off part of the jacket making it a smaller diameter.

Yep, I understand that the neck shoulder junction is where the donut grows. Some of my Lapua cases now have what feels like a significant hard spot when seating the long ELDMs past that junction. The possible jump in pressure concerns me from both a safety and accuracy issue.

You can also get a neck expanding mandrel. This will help to give some clearance, but not completely remove the doughnut.

I have a 223 mandrel and it does not help.

I have a Wilson case trimmer for which I buy the inside neck reamer ,it will ream out the donuts on a fired case. Then when you use your die check your neck size you may have to change bushing size after this step.

Can you tell me if the Wilson reamer cuts the neck from the mouth to the shoulder junction? Or on a fired case does it only somehow cut the donut? And, is it worth it?

I've used a RCBS inside neck reamer. Use it after you have sized and expanded the neck. It goes in with a slight tight fit and will cut the donut out. Just need some sort of chuck to hold it. I used one of those chuck tools that comes with a hand tap set. It's only a 12 buck tool.
https://www.rcbs.com/case-processing/ream/pilot/neck-reamers/535.html

I will have to research the RCBS reamer so see how it is designed to work.

My thanks to all of you who have taken the time to answer.

 

[Bob Wright]

K&M neck ream and turn fixed my donuts on a 280AI. Has everything you need in the kit to hold brass, chuck in a drill and hold the turning/reaming system. Wasn't cheap. I'm thinking $150 but it's been a while since purchase.

 

[slikmrc]

Anyone ever try a Lee collect neck sizing die for a donut issue?

 

[338 dude]

Yep, I understand that the neck shoulder junction is where the donut grows. Some of my Lapua cases now have what feels like a significant hard spot when seating the long ELDMs past that junction. The possible jump in pressure concerns me from both a safety and accuracy issue.

I have a 223 mandrel and it does not help.

Can you tell me if the Wilson reamer cuts the neck from the mouth to the shoulder junction? Or on a fired case does it only somehow cut the donut? And, is it worth it?

And yes, I feel it is worth it. Otherwise you would end up getting rid of the brass and having to replace it.

I will have to research the RCBS reamer so see how it is designed to work.

My thanks to all of you who have taken the time to answer.

It really depends on the reamer used to chamber your rifle. If there is enough clearance for the neck to expand when firing, it should only cut the donut on mine It lightly cut the entire neck, but much more at the donut.

 

[26Reload]

If they are 'your dedicated varmint rifles'...
Why not lenghten the chamber to seat the bullets out further.....
Order a reamer to use..hand cut the lenght you need to get your bullets seated front of the neck/shoulder jct.....