Donuts, will they always hinder accuracy?

[Bob Wright]

Mine only show up on the inside. It measures no different on the outside of the neck. I would like to know if any one has ever had them show up on the outside of the neck?

Only if you use the resizing button in a FL die. However, it moves part of the bulge to the outside but there will be a cat and mouse effect...on firing, the outside neck will be pressed into the chamber and your donut is back. I tried neck turning to remove it before I loaded them up but, that donut still formed after. Hence, the K&M turner/reamer was the ticket. No more "whack-a-mole" or cat and mouse.

 

[Barrelnut]

You can easily remove them with a RCBS neck reamer. Just attach the reamer to a cordless drill and lube the inside of the neck with some Redding Imperial Sizing Wax. That's what I do anyways....

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[Alex Wheeler]

If your seating the bullet through the donut, yes it will hurt accuracy. 2 reasons, its actually shoulder brass flowing forward and we have no control over it, so variable neck tension. The other reason is that the bullet will push it out and eventually you will have no neck clearance at that point. Not enough neck clearance will mean high es and poor grouping.

 

[Beluebow]

OK, I'll ask...I've been reloading for fifty years and done a lot of fiddling and experimenting and all sorts of A type personality, OCD reloading practices and I've never heard of a "donut"...please 'splain it to me. I'm astounded by this gap in my knowledge

So are the donuts are on the inside or outside of the brass? Or both? Thanks

Inside until they are pushed outside....and all donuts aren't the same size, some are fatter (as in farther up the case neck) than others.

As long as you are above the donut you should be GTG.

 

[Tree Farmer]

Above posts describe the problem and fix. I'll just add when I first became a recipient of "the donut" I started noticing that closing the bolt on a loaded round became progressively harder and on several loads I couldn't close the bolt. I thought my shoulder bump was wrong, but it was the excess brass being pushed outside the normal neck diameter (from bullet seating) stopping it from chambering. The good folks on this forum helped me fix the problem. Prior to, I was clueless.

 

[Bob Wright]

I like pictures....
So here is my load development going up in .2 grain increments expecting ~20 fps increases.
I had no idea it was a donut. I thought it was "sticky brass" or bullet weld. Silly me.
After digging into neck tension problems and fixes, donuts were discussed. I had them. Bad...
The first group at 200 was stupid accurate for me. I thought I was becoming a major league bench rest guy. Watch out Alex!
Then, group 2. 1 round went over the target. Group 3, well you know.

 

[Bob Wright]

Think about donuts being cartridge hemorrhoids. They're sure a pain in the ....

 

[Muddyboots]

So do you use Preparation H as a neck lube?

 

[IHFarmer07]

Been through this before.......THE best way for me was to buy a K & M neck turner with the PROPER DEGREE CUTTER for the cartridge neck/shoulder degree that you are turning, it is a MUST! Go into the shoulder just a tiny bit and it will take care of your "brass"donut problem. DO THIS EVERY TIME ON YOUR BRASS PREP.


If you decide on neck reaming, which you do you. I tried it and idk, it works but it's not that easy/efficient. You can go on amazon and get a high speed chucking reamer for cheap, put it in a drill and go.


I've seen others say that it won't affect runout but I don't see how it can't, the "brass" donut is at the bottom of the neck and is leaving the top of the neck unsupported making it have runout. I've had more runout with a donut than without.....As others have said, donuts can screw a lot up, es/sd, pressure signs and be detrimental to accuracy at long range. Depending on caliber I'd say anything under 500yrds it's not going to make a tremendous difference....what I found out is the smaller the bullet the more effect it puts on the bullet so I'd say a .224 would probably be around 300yrds and under where it won't make that big of a difference.

 

[DJ Fergus]

Been through this before.......THE best way for me was to buy a K & M neck turner with the PROPER DEGREE CUTTER for the cartridge neck/shoulder degree that you are turning, it is a MUST! Go into the shoulder just a tiny bit and it will take care of your "brass"donut problem.

If you decide on neck reaming, which you do you. I tried it and idk, it works but it's not that easy/efficient. You can go on amazon and get a high speed chucking reamer for cheap, put it in a drill and go.


I've seen others say that it won't affect runout but I don't see how it can't, the "brass" donut is at the bottom of the neck and is leaving the top of the neck unsupported making it have runout. I've had more runout with a donut than without.....As others have said, donuts can screw a lot up, es/sd, pressure signs and be detrimental to accuracy at long range. Depending on caliber I'd say anything under 500yrds it's not going to make a tremendous difference....what I found out is the smaller the bullet the more effect it puts on the bullet so I'd say a .224 would probably be around 300yrds and under where it won't make that big of a difference.

I like the old international. Looks like a late 60s model 100hp or so. Dad has an MX90. Him and my son's been trying to get a 72 JD 3020 running.

 

[IHFarmer07]

I like the old international. Looks like a late 60s model 100hp or so. Dad has an MX90. Him and my son's been trying to get a 72 JD 3020 running.

Lol thanks!! It's an early 70's model. It started as a gas 766 that dad and I picked up several years ago and the tractor really didn't get used much because of being gas, so I bought it from him, took the gas engine out, bought a buddy's 966 d414ci engine out of his tractor that he was making a pulling tractor out of and then got a good pump built along with injectors and put a latest/greatest turbo on it and it's probably between 330-450hp when in pulling mode and I farm it around 180-200hp. I pull 8mph with hand cut tires that I did. Lots of fun.

 

[fishoneil]

They can be pretty distracting, I really like the cream cheese maple bars personally, and if there are a couple of them there, I have a hard time focusing, especially since that usually means I need coffee too, and then I just get jittery, and accuracy generally goes out the window......View attachment 201664

Lab to box of donuts "Peek a Boo, them chocy ones looks the goods"

 

[Far North Hunter]

I was forming 22BR from 6mmBR Lapua brass. Found I was pushing a donut into the brass. Starting backing off the sizing die until I was close to not being able to chamber the round. Turned in the sizing die .0002, the cases chambered fine. There was a signifcan't improvement towards eliminating any donut. One pass through the expander mandrel, case chambered well and no felt donut.
I used the 40 rounds for bbl break in, no issues. I will likely neck turn however prior to the next loading to be sure I've avoided further donut issues.

 

[Bob Wright]

I was forming 22BR from 6mmBR Lapua brass. Found I was pushing a donut into the brass. Starting backing off the sizing die until I was close to not being able to chamber the round. Turned in the sizing die .0002, the cases chambered fine. There was a signifcan't improvement towards eliminating any donut. One pass through the expander mandrel, case chambered well and no felt donut.
I used the 40 rounds for bbl break in, no issues. I will likely neck turn however prior to the next loading to be sure I've avoided further donut issues.

Yeah, keep looking for it in bullet seating "feel" and if your getting velocity issues. Reaming and turning fixed my issues, maybe not yours. I just prefer to uniform my neck walls so the Redding FL bushing dies have a predictable neck tension. Good luck!