Donuts - how to get rid of!?!???

chrismc

chrismc

CGN Regular
Rating - 100%
41   0   0
Location
Prairies
So finally I have donuts forming on my 308 and 260 cases - they had been collet neck sized x 4-5 times, and were getting a bit stiff in the chamber. So did a min FL resize (bumped back the shoulder 1.5 thou), then when loading, the donuts appeared. Needless to say I stopped and took apart the rounds that I loaded.
So now I have 200 brass that i would like to get back to snuff - still very good condition Lapua brass, lots of life left - except they have donuts...

Was going to just neck trim again if I can push the donut out... but thats my dilemma - how to do with what I have at hand... or, if it fits, inside ream the neck (parts on order - Forster inside neck reamer) - i am a bit apprehensive about inside neck reaming as i don't want to thin the necks anymore, as its as thin as i want it.

Any suggestions, trials, tribulations, or remedies?
 
Inside neck reaming is a PITA. Where is the donut coming from? Brass moving forward and now you're starting to see some of the neck/shoulder junction in the neck? If it's on the inside then why is chambering a round getting a little stiff? I've never had that happen even after cases that have been fired 20 plus times at very high press and full length sized each time. Interesting. The only time I've had donuts is during case forming, such as when necking 6BR cases up to 30.

Edit: I see. The donut is on the inside but your bullets are seated deep enough to push it to the outside of the neck. Is that correct? If this is the case I would expand the necks and outside turn. Be sure to cut just a little into the neck/shoulder junction.
 
Full length resize your cases without the expander installed, then use a Sinclair expander die to push the donut to the outside of the case, now turn the necks to remove the donut.

SINCLAIR INTERNATIONAL - SINCLAIR GENERATION II EXPANDER DIES
http://www.sinclairintl.com/reloading-equipment/case-preparation/neck-turning/turning-expander-mandrels/sinclair-generation-ii-expander-dies-prod38807.aspx

Turning & Expander Mandrels
http://www.sinclairintl.com/reloading-equipment/case-preparation/neck-turning/turning-expander-mandrels/index.htm

Neck-Turning Basics
http://www.accurateshooter.com/technical-articles/neck-turning-basics/

NOTE: The expander die mandrels are flat sided and not ball shaped like a standard expander. This allows the expander mandrels to push all neck irregularities to the outside of the neck for turning.

Sinclair expander mandrel below below.

expander003_zps36696855.jpg



Donuts - how to get rid of!?!???

Plan "B" is the most enjoyable.

powdered-doughnuts_zps29dc3b8b.jpg
 
yomomma said:
Have you annealed your brass?????????????????????????????????????????????????????????????????????????????????????????????????????????
Click to expand...

Yes I have annealed my brass very 4-5 firings - these are due for their next annealing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
You don't need to anneal on a schedule. You anneal when a case mouth cracks from work hardening.
Sounds like your die is down too far. Where are these "donuts" appearing and at what point in the process?
And the "Plan B" donuts are too small.
 
The resize die is only bumping 1.5 thou - and until the bump i used a collet neck die. Here is a pic of the issue - left is a normal round, right is the donut. The COAL is right where it needs to be, if I seat out farther my accuracy drops.
IMG_1755_zpsyijmscxy.jpg
 
Are you saying the RIGHT hand cartridge was the one that was full length resized?

If so what type full length die, I'm guessing a bushing die.

Also if you look at where you stopped turning the neck on the right hand cartridge you don't have a donut problem. Looking at the shoulder of the right hand cartridge it has sized the neck "PAST" where you stopped turning the neck on the left.

So again what type die did you use to full length resize the case on the right? In the photo it looks like you pushed the shoulder back way too far and the "donut" you see is nothing more than where you stopped turning the neck.

Below the red arrow is where you stopped turning the neck and where the top of the shoulder "WAS". The blue arrow is where the top of the shoulder was moved to. I do not think you have a donut problem what I see in the photo is the shoulder being pushed back too far past where you stopped turning the neck.

IMG_1755_zpsinzwwfqd.jpg
 
Redding FL sizing die was used - the two cartridges are (left) prepped, outside turned, and loaded, unfired since neck turned (was a scatter node load so was going to pull apart rather than fire). The other on the right is from same batch, same prep, but 4-5x fired and neck sized (lee collet die) x 4-5 , them bumped 1.5 thou (measured with proper gauge) with Redding FL die, as they were getting harder to chamber... brass looked fine prior to loading, then I seated the bullet and thats what I got. I realize the red arrow is where I trimmed to, and the brass is flowing. However, if i take a primed case, there is a slight lip (donut) on the inside, and when I seat the bullet (its a 175 tmk) then i get the outer bulge. I am seating with a Forster ultra seating die.
My question is/was, how to get rid of the bulge whether it is on the inside or outside. After further reading, i will simply push a .30 mandrel inside, remove, size again, mandrel again, then outside turn.
I think the mistake I made was to go so many firings without turning. As was suggested to me, I may turn after every loading just to keep the bulge from ever forming. I just started turning last fall, and this is the first time I have had anything like this pop up. Learning curve.

And i will be aware of pushing the shoulder too far back - it does look like that, even tho the gauge says 1.5 thou - which does make sense as one would think the expander ball would have pushed the lip/donut out a bit.
Thanks for the advice!
 
Last edited:
Do yourself a favor and get a Forster Bench Rest Full Length die and stop using your Lee collet die. With the Forster die you can produce ammunition with the minimum of neck runout and be better off.

Right now you have something very strange going on and I do not think you have a donut problem. You sized the neck past where you stopped turning the neck and what you are calling a donut is now the thicker part of the neck where you stopped turning. Also when neck turning you only need to remove 75% of the neck material and it looks like you removed 100% and reduced the neck thickness excessively. All you need to do is skim the necks to remove 75% of the high areas and then stop.

Below is a Forster bench rest full length die with its high mounted expander. The expander enters the case neck when the neck is still centered in the neck of the die. Meaning the neck can not be pulled off center by the expander ball and thus reducing neck runout to .001 or less. The Forster expander and spindle assembly system works so well I replaced all my RCBS expanders with Forster units and greatly reduced my runout.

Sizer_Die_011_zpst2zm6m7y.gif


Also you will be better off full length resizing your cases, please read below and note it was written by a member of Team Lapua USA.


KTLapua-b_zps8d1abc2c.jpg
 
bigedp51 said:
Do yourself a favor and get a Forster Bench Rest Full Length die and stop using your Lee collet die. With the Forster die you can produce ammunition with the minimum of neck runout and be better off.

Right now you have something very strange going on and I do not think you have a donut problem. You sized the neck past where you stopped turning the neck and what you are calling a donut is now the thicker part of the neck where you stopped turning. Also when neck turning you only need to remove 75% of the neck material and it looks like you removed 100% and reduced the neck thickness excessively. All you need to do is skim the necks to remove 75% of the high areas and then stop.

Below is a Forster bench rest full length die with its high mounted expander. The expander enters the case neck when the neck is still centered in the neck of the die. Meaning the neck can not be pulled off center by the expander ball and thus reducing neck runout to .001 or less. The Forster expander and spindle assembly system works so well I replaced all my RCBS expanders with Forster units and greatly reduced my runout.

Sizer_Die_011_zpst2zm6m7y.gif


Also you will be better off full length resizing your cases, please read below and note it was written by a member of Team Lapua USA.


KTLapua-b_zps8d1abc2c.jpg
Click to expand...

How do you beat zero induced runout after neck sizing?

I hope all my competitors read this info on FL sizing. I think we should make it mandatory..... for everyone else. And oh, why worry about what reamer vs FL die... it's all good.... rattle, rattle, rattle. Free fitting brass... perfect. I really appreciate this info.. please tell EVERYONE that competes in F class.

Jerry

PS By the way, LR F class is a 1/3 min game nowadays.
 
Did you try firing your reloads - to re-fireform your brass? I would think that this is similar to when you are re-shaping brass for another calibre (i.e. Hornet to K-Hornet). Your die and your chamber look to have slightly different specs so I would think that when you bumped the shoulder back it deformed the brass slightly to conform with the sizing die but once you fire the brass it would now conform to your chamber at which point you could check to see if you need to trim the brass and than just neck size as usual. I have mild donuts on my .338 LM brass from my FL re-sizing (my chamber and RCBS dies are slightly different) but they seem to go away after I fire them so I don't worry about it. I think your donuts are more pronounced because you neck-turned your brass and I didn't bother with mine. My recommendation is load up a few and shoot them and see if your donuts go away...
 
Mystic Precision said:
How do you beat zero induced runout after neck sizing?

I hope all my competitors read this info on FL sizing. I think we should make it mandatory..... for everyone else. And oh, why worry about what reamer vs FL die... it's all good.... rattle, rattle, rattle. Free fitting brass... perfect. I really appreciate this info.. please tell EVERYONE that competes in F class.

Jerry

PS By the way, LR F class is a 1/3 min game nowadays.
Click to expand...

Glad you spoke your mind, so here is my opinion of my Lee collet dies vs Forster dies.

lee_zps8asygcdv.jpg


Have a nice day!
 
You must log in or register to reply here.
Back
Top Bottom