doughnuts anyone??

[Hutch]

been doin some readin as of late, and have come across a term several times and for the life of me cain't seem to grasp ecxactly what this doughnut thing is.

obviously, they aint good....So, what is it? how do you recognize it? can you git rid of em? what are the dangers of leavin em be?? can you leave em??

I've got a picture in my head of what I think it MIGHT be. Just needin some clarification.....Thanks all




Hutch

[trappst]

doughnuts are a build up of brass material at or near to the neck/shoulder junction. Causes can vary but from what I've read and witnessed......the too I hear of most are lots of neck sizing only and necking down brass to form wildcats. Easy way to check for 'em is to drop a bullet in the neck of a fired case...if it stops, you've got problems. You can also use a paper clip with a slight bend to check the area.

To get rid of 'em, you'll need to either turn necks or ream the inside of the neck. They are bad b/c if you seat a bullet deep enough in the neck, the doughnut will increase tension on the bullet to a point where pressures can increase drastically. Plus, they can't be good for run out etc...

I've seen a couple different theories on leaving them be.......Obviously, if the bullet makes contact they need to be removed. However, if the bullet isn't seated deep enough to contact the doughnut there's really no danger. On the other hand, I've also read that doughnuts may disturb the powder burn process thus creating issues in accuracy, velocity spreads and the such.

Hope that helps!

[dfrosch]

A doughnut is an area at the shoulder end of the neck that the wall is thicker than the rest of the neck wall.

Most brass has a thicker wall on the shoulder than the neck. If you resize 243 cases to 260 or 7mm-08, you will actually make part of the shoulder become part of the neck. This can be really bad if you seat a bullet down to this area. It is possible to get an interference fit between the bullet, case and rifle chamber.

Leaving them is generally not a good idea. It can be removed by either neck reaming or expanding the entire inside neck diameter to a uniform dimension and turning the neck all the way to the shoulder.

[stevec]

I get them in my 6-250AI but they are just below where the bullet seats so they dont cause prablems with loading. I used a inside neck reamer to get rid of them but couldnt tell much diference(if any) on target at 600 and 1000yds. Most people say you have to get rid of them for extreme accuracy. I get rid of them because they are a confidence killer for me. ;)

Steve

[BillPa]

been doin some readin as of late, and have come across a term several times and for the life of me cain't seem to grasp ecxactly what this doughnut thing is.


I've got a picture in my head of what I think it MIGHT be. Just needin some clarification.....Thanks all


Hutch


Your classic donut (ie; doughnut, dough nut, dog nut and etc). They form inside the brass at the neck-shoulder junction.

http://i43.tinypic.com/2nuq2jr.jpg

To check for them them I use a gage pins.

To remove them I use three methods.

1 & 2 are basically the same thing, cutters I make myself for a Sinclair NT-1000 turner or the K&M neck turner with the fluted carbide pilots.
http://www.kmshooting.com/images/products/med_1158998739.jpg

The third way, I'll expand the necks to move the brass (donut) to the outside then neck turn them just nicking the shoulders with the cutter.

They're not a problem unless your seating bullets into or past the neck junction.

Bill

[birdie]

After reading this post I realized this pertained to my problem on my 6 br silen barrell I installed on my bvss model 12 last year. It seemed to take at least 150 or so rounds before I found a decent load using 105 a-max bullets and v-135. I shot them a few times and all of a sudden noticed pressure issues. Coincidentally I noticed the very long a-max bullets would only go in to the shoulder area. I am using wilson hand dies neck sizing with lapua brass. My question is this; if I start with new brass and a full length redding die with bushing will I still get donuts? Or should I buy a custom die? I always have this problem of trying to run before learning to walk. I have not bought a full length die yet. Money is tight right now and I need to slow down and make better dicisions on the items I buy. As always thanks in advance. P.S. I did not know if I should start anew topic on this or not. Please advise

[Hutch]

no worries here birdie.......



Hmmmmmmm.........I think I may have a bakers dozen ::)



Hutch

[Bad Water Bill]

I had the same problem when I made 20 VT cases out of 223. The major problem was the donuts were not sugar coated. :)

The solution was to send a fired case to Forster and have them cut a special inside neck reamer for me. This was for a Shilen bbl with a close chamber. All is good now.

[trappst]

Yep, I get 'em pretty bad necking down 6.5x47 Lapua brass to 20 cal!!! After I complete the neck down process, I run a Sinclair expander mandrel in the neck and then turn necks to .014". It's a complete clean up of the neck and I also tun down into the shoulder very slightly.

No 'mo donuts!

Birdie, to answer your question: Yes, if you use a FL die you won't get the donuts b/c the die is pushing brass throughout the case and not just the neck area. However, when using a bushing type die there is still a chance a small donut may form...Redding bushings aren't made to size the neck all the way down. It's close but there is a very small area that doesn't get sized.

Bad Water Bill's solution sounds like a good way to get the necessary tool to be donut free. That way you could continue using the brass you already have.

[birdie]

I like the replies I am viewing and hope more people not only give possible soloutions, but relate their experiences so shooters like myself might learn from them. This is the exact reason I decided to become a paid member a while back. Once again thanks...

[Hutch]

Finally got a chance to sit down a nd gander at my stuff.....couldn't find any doughnuts?!? But! this is what I do got, and what inspired my question to start with.

http://img.photobucket.com/albums/v645/Hutch1golf/DSCN0328.jpg

It's like this on almost every piece of brss I have, now mind you I'm using the winny white box, and this has been the absolute worst brass I've ever handled. After 2 boxes(40 rnds) I've had to cull 11 cases due to split necks.

Here's a few more.


http://img.photobucket.com/albums/v645/Hutch1golf/DSCN0330.jpg

Not quit sure how to proceed with this batch of brass....other than pick up some Lapua ;)


Thanks fellas.....

Hutch

[Budweiser360]

Does anyone still get the "doughnuts" when using a collet neck sizing die?

[docsleepy]

Are you neck turning for a tight neck chamber? If not, then there might be limited benefit from any further neck turning if your brass already fit (despite the fact you have low spots that haven't yet been turned, from your photos). The idea of neck turning/tight neck is somewhat to just reduce the wiggle of the mouth within the chamber to a minimum, so the aft end of the projectile starts in exactly the same point each time. The forend of the projectile may sometimes be jammed in, so that IT starts in exactly the same point also. Then you have repeatable results.

If the chamber isn't a tight neck chamber, then there is probably a diminishing return from uniforming (turning) the necks, because you increase wiggle room. I'm not an expert enough to know in a factory chamber.

As far as the doughnuts, k&m sells a pilot for their neck turner that is also a cutter. I think it was not cheap, but it worked well for me.
I tried the idea of pressing the doughnut to the outside and re-turning, but you end up turning a long way onto the shoulder and for a newbie like me, that is a bit scary. If you make a mistake, you end up with a neck that suddenly comes off the case and stays in your chamber---making completion of the match extremely difficult. I was at a match where that happened to another fellow. Using the inside reamer from k&m is quick and painless and does the job.

[BillPa]

I tried the idea of pressing the doughnut to the outside and re-turning, but you end up turning a long way onto the shoulder and for a newbie like me, that is a bit scary.


The trick to that method is grinding the leading edge of cutter (bit) to match the shoulder angle with a slight radius on the corner. When you make the cut the angle on the cutter contacts the shoulder but gets into the junction without going too deep into it. It also helps prevent length over-under cutting regardless of the neck length. When the cutter contacts the shoulder your there.

The case on the left was turned with a 20 degree cutter after being necked down prior to forming. The case on the right is a formed piece of brass.
http://i40.tinypic.com/2rnwtfm.jpg

Here is a good read on the subject.
http://accurateshooter.wordpress.com/2009/01/31/tool-tip-optimize-your-cutter-angle-for-improved-neck-turning/

Bill

[Hutch]

Docsleepy, I'm not sure I can agree to the wiggle room idea. After all, a fireformed case should fit the chamber with 0 headspace/ airgap between the shoulder on the brass and the shoulder in the chamber, that should eliminate any "wiggle" To my way of thinkin anyway, and I sure aint no expert, so......


The reason I turn necks is to uniform the brass (obviously) ::) If the neck is thicker on one side than the other then the bullet will never be aligned with the center of the bore. Generally, I'll only knock the high side off the necks, that way when I size them the necks won't get pushed to one side or the other.

The thin spots on this brass worried me enough to purchase brand spankin new brass. All the winny brass is goin in the brass scrap bucket!!

To all, be well!



Hutch

[birdie]

;) I just received my new redding type s bushing style full sizing die. Tomorrow I was planning to run some new lapua brass through it with a ..266 bushing, load up some rounds and hopoefully go to the range sunday. I am hoping this will hellp ;my donut problem. I could fire it once and have my freind cut the brass at the shoulder area wher the donut area occurs. I dont even know if this is possible as I am inexperienced in neck turning. Please give input.... thanks birdie

[Hutch]

hey birdie, these doughnuts are on the inside of the case neck. with new brass there should be no doughnuts. The pics i posted were a conditiuon i was encountyering that I thought might be related to doughnuts.....they weren't....just crappy brass.

Since your new to reloading, just keep things simple, go slow, don't go out an try to shoot bugholes right out the gate, you'll frustrate yourself and there goes all the fun, Then you won't wanna do it anymore and end up sellin me all your stuff waaaaaay cheap just cause it pisses you off to look at sittin there ::) ;)



Hutch