Thread: Doughnut issues

Righto. I have a wee issue that I dont think is major but I will put it to the other anal reloaders like me out there on the forum who can have some imput and maybe a soloution.
I have always used a Forster Bonanza press and use Redding type 's' bushing dies. Others that use the Redding bushing dies know that when when FL or neck sizing they can in some instances leave a wee doughnut at the shoulder junction. Not really considered a problem in standard cases.
I get them but they are very slight (hardly visable) on my 6.5-06 cases and it does not seem to be a problem concerning accuracy. Maybe it could get better without them?

My real concern is I am getting an AI cartridge and everything I have read, written buy successfull LR shooters using this cal is that they also normally use Redding type 's' dies. But because of the doughnut you get with the bushing dies, they have either had a die made to spec or used a lee collet die. The latter is of no use in a Bonanza press.
I have purchased the dies and they have already arrived prior to finding out about this potential problem.

A seated projectile in an unturned Lapua case is .294 in my 06 and I am assuming it will be close to the same in the new AI using Lapua brass. The reamer has a neck of .297 giving .003 clearance on unturned brass. I will most likely take .001 off the neck after neck wall and weight sorting.
Considering the case neck will expand on firing to .297 and settle around .296 essentially giving me a .001 clearance until sized. The concern for me is the base of the neck will still potentially be .296 if the die forms a doughnut after sizing.
I believe neck tension may be affected and worry but doubt the case could almost headspace on the base of neck and not the shoulder.
Do others think this is a worry or am I being pedantic. If it is a concern, short of buying a spec die (I will if I have to) I would appreciate any ideas how to get rid of them if I get the doughnuts.

Cheers in advance

You could always make sure you throat the chamber for the bullet you want to use so it is nowhere near the "doughnut" when seated.....

You are being pedantic. No offence.

same as this ?

Dave, I use type S only for all my calibres and have yet to come across this porblem. The donut will only form from brass flow, not sizing. The bush does not size all the way to the shoulder junction, and the step is only that, a step, not a thickening of brass. Donut will form in some cals easier than others. I looked into it and the best way to keep on top is to inside ream. I have a Forster lathe that I can get inside cutters for but have not yet needed them. You will rechamber? As KiwiGreg said you couold set it back a touch and cut the throat long enough (for your intended pill) that it will not need to be seated into the junction (where donuts may form).

Originally Posted by madjon_

same as this ?Attachment 1546

Yup. But possibly worse in the AI.

Originally Posted by kiwijames

Dave, I use type S only for all my calibres and have yet to come across this porblem. The donut will only form from brass flow, not sizing. The bush does not size all the way to the shoulder junction, and the step is only that, a step, not a thickening of brass. Donut will form in some cals easier than others. I looked into it and the best way to keep on top is to inside ream. I have a Forster lathe that I can get inside cutters for but have not yet needed them. You will rechamber? As KiwiGreg said you couold set it back a touch and cut the throat long enough (for your intended pill) that it will not need to be seated into the junction (where donuts may form).

Thanks James I have thought of inside reaming if I see a ES problem. The cartirdge reamer is on its way so I cant change the specs on that. I will see how it goes. As I said I dont really think it is a problem but I have never owned an AI cartridge before and I will end up with 2 in a month or so. I am just trying to learn and avoid any potential problems .

Originally Posted by R93

Thanks James I have thought of inside reaming if I see a ES problem. The cartirdge reamer is on its way so I cant change the specs on that. I will see how it goes. As I said I dont really think it is a problem but I have never owned an AI cartridge before and I will end up with 2 in a month or so. I am just trying to learn and avoid any potential problems .

Just got my first AI today too . Will do a write up shortly.

Originally Posted by Savage1

You are being pedantic. No offence.

No offence takin. Its a compliment as far as reloading accurate ammo goes

Originally Posted by kiwijames

Just got my first AI today too . Will do a write up shortly.

Looking forward to it James. If you dont notice a problem with the bushing dies I doubt I will. I spose you have taken the day off work to play?

Nah, still at work. I needed the die grinder.

Originally Posted by kiwijames

Nah, still at work. I needed the die grinder.

Oh. Whats up with that?

The doughnut which can be caused by sizing and brass flow, normally builds up after a few firings in the neck shoulder junction area, alot of people don't realize that they have a small doughnut causing neck tension issues. Because of this all of my throats are set up so the rear bearing surface of the bullet stays at least 0.020 thousands in front of this area as already stated above. One tool that I found very helpful in one rifle I used to own with a very short throat is the K&M carbide neck turning mandrel with doughnut cutter, you just expand you necks with the expander mandrel then run it over the carbide turning mandrel and it will cut the doughnut away with out cutting any other part of the neck, worked a treat.

Originally Posted by Terminator

The doughnut which can be caused by sizing and brass flow, normally builds up after a few firings in the neck shoulder junction area, alot of people don't realize that they have a small doughnut causing neck tension issues. Because of this all of my throats are set up so the rear bearing surface of the bullet stays at least 0.020 thousands in front of this area as already stated above. One tool that I found very helpful in one rifle I used to own with a very short throat is the K&M carbide neck turning mandrel with doughnut cutter, you just expand you necks with the expander mandrel then run it over the carbide turning mandrel and it will cut the doughnut away with out cutting any other part of the neck, worked a treat.

Thanks for that I will keep it mind if I have any problems.

Internal donuts gave me a problem in a 280ai after the first firing with nosler brass, checked by pushing a bullet into a fired case, it would stop when the boat tail/bearing surface
junction of the bullet hit the donut at the neck shoulder juction, I cut them out them with a forster interneal neck reamer, cheap and very simple.The next lot of brass hasnt given any sign of donuts at all and the laupa brass in my .243ai is fine after 3 firings but Im still checking as the round count rises.All are sized with redding bushing dies but I wind the adjuster out a touch so I dont size all of the neck. About 3/4 of the 280ai and 7/8 on the .243ai