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View Full Version : Is there a way to remove the donuts?


22_boomer
02-09-2012, 09:55 AM
I read someplace on here that the donut that forms at the junction of the case neck and shoulder can be removed and I was wondering how it was done? I have a nice little 17 caliber cartridge that's formed from a much larger caliber cartridge and I feel I have a donut problem at the base of the neck.

wally bennett
02-09-2012, 10:53 AM
I read someplace on here that the donut that forms at the junction of the case neck and shoulder can be removed and I was wondering how it was done? I have a nice little 17 caliber cartridge that's formed from a much larger caliber cartridge and I feel I have a donut problem at the base of the neck.

Hi BOOMER.

I had this problem when forming 17A/H cases fom 22H brss and i was not forming the first form pass enough so on the second form die it was buckeling the shoulder/body area.
On the cases i buckled/doughnut i just annealed the area a bit further down than i usualy do and they fireformed to a normal shape.
Wally

Mike Casselton
02-09-2012, 12:07 PM
K&M makes a carbide donut cutter just for this purpose.

I was really hoping you needed help with the other kind of donuts. I got a hot cup of coffee sitting right here....

sicero
02-09-2012, 12:09 PM
I have a carbide cutter with my K&M neck turner that is supposed to
remove the donut. Kenny

22_boomer
02-09-2012, 01:18 PM
K&M makes a carbide donut cutter just for this purpose.

I was really hoping you needed help with the other kind of donuts. I got a hot cup of coffee sitting right here....

I know what you mean about the other kind of donuts -- I had to go on a diet because of bad health and even just pictures of donuts drives me nuts. I had a hard time writing this thread this morning -- had that cup of coffee and nothing to go with it.

To you and Sicero -- I'll look up that K&M carbide donut cutter and thanks! I was hoping somebody made one.

edit to add; Wally, I have a real hard time annealing this really short cases and I'm not sure I could do it well enough to help with those neck donuts.

Joe O
02-09-2012, 03:19 PM
You might try stepping down the sizing with an intermediate step,and anneal after the first reduction.I was bulging the shoulder on 218 Bee brass,when taking it to 20 cal on one pass.No donut,but a 232 bushing,annealing,then a
.220 final bushing worked better.Fireforming takes the shoulder out to 30*,then all is well.

CRT makes a very nice annealing,shell holder to hold the neck in the flame.Tool fits in a cordless screwdriver.

http://www.customreloadingtools.com/

wally bennett
02-09-2012, 03:20 PM
I know what you mean about the other kind of donuts -- I had to go on a diet because of bad health and even just pictures of donuts drives me nuts. I had a hard time writing this thread this morning -- had that cup of coffee and nothing to go with it.

To you and Sicero -- I'll look up that K&M carbide donut cutter and thanks! I was hoping somebody made one.

edit to add; Wally, I have a real hard time annealing this really short cases and I'm not sure I could do it well enough to help with those neck donuts.

I must be thinking of a different doughnut i thought you ment the bulge caused by forminf die but if you cut this it will weaken the case.
A for annealing if you hold the case in a shell holder and be carefull with the flame the shell holder will act as a heat sink and you can anneal ok
Wally

GrdhgKiller
02-09-2012, 06:24 PM
I have used both the K&M neck turner with the inside neck reamer that come only on the carbide cutter as I remember. I have also used the Wilson inside neck reamer that is use with the Wilson trimmer and used on fired cases only. You must remember in using the K&M reamer to first full size cases then only run the neck expander up to the donut. If you run the expander in all the way you are pushing the donut back out to the outside of the case neck and you will not be reaming out most of the donut. In the case of the Wilson inside neck reamer for fire cases I always felt if you had an overly generous chamber neck that the excessive case expansion would not allow all the donut to be removed. Here is an article that has a section talking about the donut and removal. http://www.6mmbr.com/260AIforming.html Also the K&M outside cutter which has a 30 degree shoulder cutter as I remember will allow to slightly cut into the shoulder to removed the thicken brass the has been pushed down into the shoulder area during the forming process. If your case has a shoulder angle other than 30 degrees you will have to determine if you can cut past the shoulder neck juncture. This article on neck turning talks about this and other aspects of neck turning. Bill http://www.6mmbr.com/neckturningbasics.html

I thought I would add a link to K&M that mentions in the instruction tab cutting into the shoulder which you might want to do to formed down case necks. http://www.kmshooting.com/catalog/neck-turner-tools/micro-adjustable-neck-turner_body-only_standard-pilot.html I might add that I also have used pin gauges to discover the presence of donuts. If the gauge can enter the case mouth but is stopped before it goes past the shoulder/neck juncture you have a donut. Then try inserting smaller diameter pin gauges till they pass into the case to determine the amount of the donut present. I bought a cheap set from Wholesale tool which I have found useful in other aspects of reloading. http://www.wttool.com/index/page/product/product_id/17821/category_id/17561/product_name/Pin+Gage+Sets+%28WT%29

jholp
02-09-2012, 08:58 PM
The brass will tend to thicken right where the shoulder joins the neck, hence it forms a doughnut that restricts the gas flow down the neck of the case.

Purchase the K&M device, the one that has the face of the bit ground to remove the dounught. They make two and one does not have this cutter.

Size the case neck first, then pass the neck over the K&M expandron, then run the cutter thorugh the neck. If there are doughnuts you will feel it when the cutter removes it/them.

The 1000 yard bench rest shooters check and fix this problem quite often.

John

22_boomer
02-09-2012, 11:25 PM
It took me a while to find a video on line that showed how the K&M fluted neck turn mandrel actually worked. I believe it is just what I need. I realized some time back that I must have the donut problem when I tried to seat some 20gr 17 caliber V-max bullets a little deeper and they refused to go. The little 17gr V-max bullets had no problem but they are boat tailed. I'm doing a bit of a rebuild on my 17 Reed Express rifle and this is one of the details that needed to be addressed.

J.Dant
02-10-2012, 12:36 AM
Not to hi-jack this thread but how do you positively know that you have a
donut?

Thanks, John.

Mike Casselton
02-10-2012, 02:48 AM
The sticky sugary goo on your fingers.... Well, that would really mean HAD, not have. ;^)

22_boomer
02-10-2012, 10:01 AM
Not to hi-jack this thread but how do you positively know that you have a
donut?

Thanks, John.

there is ring right at the base of the neck. I discovered it when I tried to seat some 20gr bullets a little deeper and they wouldn't go. I inserted the end of a paper clip and can feel it. It's not on all my brass and I guess I need to check if it only happens with one brand of brass or not.

Thankfully these donuts are not sugar coated!

GrdhgKiller
02-10-2012, 05:26 PM
Check out the first link I provided. About half way down is a picture of a sectioned case showing the 'donut'. The donut can occur when forming the cases down to smaller calibers, causing brass to be pushed down and thicken. You will often find out you have a donut when you try to seat a flat base bullet and encounter a lot of resistance. Sometimes you can seat a boat tail bullet because the taper base won't reach or contact the donut. As I mentioned before pin gages can also reveal the presence of donuts.

Also remember when you go to remove donuts you have to go where the donut is located. After firing a round the donut is pushed to the inside of the case neck. It can then be removed then with a reamer for fired cases. If you use a neck turner with reamer you can either run the neck expander part way in to the donut and stop. Then the reamer will remove the donut. If you run the neck expander all the way in you have essentially pushed the donut back to to outside of the case neck. In the situation the outside cutter will remove the thicken brass 'donut' if you cut down slightly into the neck/shoulder juncture. Bill