Steve, Forester make three types of dies. PMA3 is referring to their bushing bump dies. They will full length resize your brass and you can get any size bushing you wish to achieve the neck tension you desire. They also resize the entire length of the neck so there should be no more variance at the neck shoulder junction. You should still re-turn your necks after firing them twice since using this type of bushing forces any extra thickness at the neck shoulder junction to the inside. Result= donuts. These dies should only be used after brass has been fully prepped and trimmed to final form. dedogs
Donuts
- Thread starter CHROME
- Start date
I tried but I am lost. How does the chamber "create/cause" or not "create/cause" a donut?
I think what he means is that the shallower the shoulder angle, the greater the tendency for the brass to flow forward into the neck/shoulder junction area upon firing. Ackley improved cartridges for example, hardly grow forward at all with the sharp @40 degree shoulder angle. Other cartridges like a 22 250 etc with shallower shoulder angles tend to push the body/shoulder brass forward easier into the neck shoulder junction area.....If I'm wrong, please correct me.
I have a donut problem right now. 80% of my lapua 22-250 cases that I've neck turned have formed donuts inside the neck at the shoulder junction after 4-6 firings. I also have a handful of Winchester cases that I got to practice neck turning. They have the same number of firings but the donuts are less pronounced. I have been turning slightly into the shoulder like recommended but they still formed anyways.
The issue comes in where I seat my bullets. I use 75gr A-maxs and the base of the bearing surface just starts to hit the donut during when I'm seating. Depending on the donut itself this causes my seating depth to vary by as much as .005" and naturally I can't seem to hone in on the ES I'm looking for. I am already slightly jammed so if I hit a big donut while seating it could cause some pressure problems. I prefer light neck tension but those donuts just won't give much.
I neck turn using K&M tools but the expander doesn't even touch the donut so I can't iron it out and trim it off. What I feel I need is a reamer about .0005" bigger than a bullet to slide in on a fired piece of brass without touching the neck and cut the donut down a little bit. When you slide a bullet into a fired case of mine it doesn't touch the neck at all but you can feel it bottom out hard on the donut. That bullet will sit there on the donut usually .010-.020" before I've reached my desired seating depth.
The issue comes in where I seat my bullets. I use 75gr A-maxs and the base of the bearing surface just starts to hit the donut during when I'm seating. Depending on the donut itself this causes my seating depth to vary by as much as .005" and naturally I can't seem to hone in on the ES I'm looking for. I am already slightly jammed so if I hit a big donut while seating it could cause some pressure problems. I prefer light neck tension but those donuts just won't give much.
I neck turn using K&M tools but the expander doesn't even touch the donut so I can't iron it out and trim it off. What I feel I need is a reamer about .0005" bigger than a bullet to slide in on a fired piece of brass without touching the neck and cut the donut down a little bit. When you slide a bullet into a fired case of mine it doesn't touch the neck at all but you can feel it bottom out hard on the donut. That bullet will sit there on the donut usually .010-.020" before I've reached my desired seating depth.
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dmoran
Donovan Moran
Because no one is going to ask I will; what happens to the cases if you do not turn the necks after 5 firings?
Just a reminder; I have chambers that will never cause a do-nut to form, I have chambers that create do-nuts by design meaning I can count on it and I form cases that require the donut to be removed before I can finish forming the case. There is something about firing, sizing and forming a case most reloaders do not understand.
Last night I was sorting through gun parts, I am short on 6.5mm55 bolts meaning I am going to screw the 6.5mm55 barrels into Mauser actions that are complete. During the digging I found 2 old set of dies, complete with neck reamers, I may never need them but I have them just in case.
F. Guffey
The only chamber I can think of that wouldn't cause donuts is one with a straight walls . Larry
Larry. I have never had a 30/30 case form a donut, I have never had a 303 British case form a donut and then there is the 30/40 Crag, Sunday I went looking for parts, I found a box full, the man I got the parts from said he would give me all the 30/40 Crag parts I need and then I remembered, there is nothing I like about shooting one and then there is the one lug and the tapered case. I have never had a donut form in a 30/40 case. P.O. Ackley was the best thing that ever happen to cases with a lot of tapper and then there is the EPPS.
F. Guffey
Po Ackley found it slowed the stretch from moving . Because of the sharp shoulder but it didn't stop the donuts from happing. If anything it increased them . The only way I can think of ream them out or seat the bullet foward of them. I have found longer free bore was the best . I only size halfway on the neck to hold bullet . My bump die sizes the neck to 269.5 the last half of the is .265 . When I bump my cases I can with pressure from my fingers push the bullet to the donut . But I still seat the bullet foward of the donut . So far the donut has not changed my fps but I have only fired them 25 times
The more I anneal the more I have to trim . Larry
The more I anneal the more I have to trim . Larry
Again, I have chambers that have never formed a donut, I have chambers that form donuts by design and I form donuts with bad habits. I form donuts that almost close the neck off and must be removed before I can finish forming the case.
F. Guffey
The reason I neck turn is because I bought an off the shelf Shilen savage pre-fit. It definitely has a tighter neck than my factory barrel. When I tried to stick my modified comparator case into the chamber it would not go, the neck diameter was too wide. A fired case from a factory chamber would not go either. My best attempt at measuring it was .252" so I started cutting my necks to .0125". That gave me .003" release which has worked well. The bullet just barely drags in a fired case, until it hits the donut that is.
What I tried tonight was taking, to the best of my ability, a rat tailed file and carefully working the donuts until they no longer contacted a bullet. Then I took the neck trimmer and cut into the neck shoulder junction a bit more. I only tried it on 5 cases which I'll shoot first to make sure the necks don't come off.
I do not want to make new brass for this barrel, I suspect it's near the end of its usable life and I have another one waiting to go on.
What I tried tonight was taking, to the best of my ability, a rat tailed file and carefully working the donuts until they no longer contacted a bullet. Then I took the neck trimmer and cut into the neck shoulder junction a bit more. I only tried it on 5 cases which I'll shoot first to make sure the necks don't come off.
I do not want to make new brass for this barrel, I suspect it's near the end of its usable life and I have another one waiting to go on.
Every case I ever saw where a neck came off, the barrel was ruined. It is amazing what running a neck down a barrel case can do. Matt
Sounds great; problem, I can not ream the neck without case body/neck support. I do not use pin gages but when I attempted to ream the neck of a case without neck support I tapered the neck because the neck is not supported until the reamer gets down to the neck shoulder juncture. This should not be mew to anyone except those that believe they invented neck turning. I have old Lee dies in sets called Target Model, the Lee reloading set came with a die that was a neck sizing die with a guide in the top of the die for the reamer.
And then when a reloader turns the neck they use a pilot to support the neck from the inside.
F. Guffey
RCBS makes sizing dies that are designed to be used as a neck reaming die. They are expensive and do not include the reamer.
http://www.midwayusa.com/product/411579/rcbs-neck-reamer-die-234-rcbs
F. Guffey
http://www.midwayusa.com/product/411579/rcbs-neck-reamer-die-234-rcbs
F. Guffey
One other possible way if the brass is soft enough would be to expand the necks up to .243, then turn them, then size them back down. I tried reaming necks on 22 250's once and didn't like the results.
After thinking about it for a bit I purchased a 5.7mm 2 fluted reamer type drill bit off ebay. That comes out to .2244" which is slightly larger than a bullet. I was able to sneak in past the neck and whack the donut down on my good cases. Just using my fingers the bit was plenty sharp to cut out the excess brass buildup.
The results were good and even the cases I trimmed the neck shoulder junction down on worked okay too
The results were good and even the cases I trimmed the neck shoulder junction down on worked okay too
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