Doughnuts in the necks

[DHuffman]

I just did 200 that have been LCD sized since neck turned so I'm gonna have to throw the BS flag on that LOL

[gman47564]

On what dave..

[gman47564]

I have never had a doughnut form using a redding body die and a lee collet die .. and thats in several carts..

[bikemutt]

You guys helped me when, purely by accident, I discovered my 11x, freshly fired,  Alpha brass cases were fighting being chambered. At the time I was trying the bolt drop method for finding the lands. The solution, in that case, was to turn the necks.

In any event, that brass was always seated with a LCD. I wonder now if instead of an inside doughnut, it ended up as an outside doughnut of sorts?

[gman47564]

I had all these cases with the doughnuts loaded when i made this post.. i shot 25 of them awhile ago.. the doughnut doesn't seem to be affecting accuracy at all.. i went 10 for 10 on a 2 inch plate at 430 yards.. however i still want them gone.. so on the cases i just fired i ran my reamer in them.. what kind of suprised me was the reamer cut a little off each case just inside the mouth.. then wouldn't cut anything till it got to where the doughnut was. And then it was very little.. just suprised me it cut some off at the mouth..

[mnbogboy]

Grant I've noticed the exact same thing in the past. My routine at the time was to use a new bullet in the fired case to check for the donut. Often the new bullet would not slide in easily as the very beginning of the case mouth held it from easily dropping in. I tried to blame the tight case mouth on the donut itself because they seemed to fall hand in hand. Once the reaming had eliminated the donut then that phenomena went away on all cases.

[DHuffman]

I had all these cases with the doughnuts loaded when i made this post.. i shot 25 of them awhile ago.. the doughnut doesn't seem to be affecting accuracy at all.. i went 10 for 10 on a 2 inch plate at 430 yards.. however i still want them gone.. so on the cases i just fired i ran my reamer in them.. what kind of suprised me was the reamer cut a little off each case just inside the mouth.. then wouldn't cut anything till it got to where the doughnut was. And then it was very little.. just suprised me it cut some off at the mouth..

BS on the earlier post IME that you won't get donuts using the LCD

A lot of what I'm saying may not apply to what a lot of you guys are doing because in my particular instance I'm running .0102" - .0105" necks on my Lapua Imp. I'm convinced it's a donut making machine, they're not horribly bad and they're not hurting anything but I'm sure some day after traveling several hundred miles and paying to enter a match they are going to become a problem if I dlllllon't cut them off occasionally.
So when you are running necks that thin you tend to be pretty careful about taking any extra off anywhere by inside reaming. Even if we size with an LCD then use the expander mandrel prior to turning we are getting spingback, out with the LCD and in with the mandrel so I seriously doubt we're getting all those imperfections "pushed to the outside" so we can turn them off.
When I turn the donuts off I set my cutter so it starts making a cut about halfway between the mouth and the neck shoulder junction and it obviously removes a lot of the donut but a tight pin gage verifies there's still a little left inside. A reamer would catch some more but like I said I don't want the cross hatch reamer marks or the cuttings in my necks and brass.
Perfect is not going to happen but I'm happy with manageable.

I've shot almost exclusively 40° shoulder cartridges the last 4 years. 6 BRA, 7-08 Imp, 6.5x47L Imp and a Dasher. With the exception of the Dasher being a no turn neck the others have all made donuts. For me the improved accuracy and the almost non existent brass growth is definitly worth the trade off maintaining donuts. I think the 40° shoulder inhibits brass growth because it's "balling" it up in that sharper neck shoulder angle.
Every 5 firings I size, trim, turn & anneal my brass and consider it fresh and good to go for another 5

When I shot that .865" group in competition at Elbow Lake MN and backed it up with a 1.2" then backed that up with a 1.778" four target agg to win LG Group, Score and Overall that brass was on it's 7th firing and had the above processing after it's 5th firing. A month later in the 2019 600 yard Nationals it had at least four 1" groups out of an 8 target match and the brass was on it's 8th or 9th firing or annealed + 3 or 4 firings.

After 4 or 5 firings it gets hard to get a consistent shoulder bump because IMHO I'm fighting the excess brass in the neck shoulder junction not because the brass is getting hard from lack of annealing so I process them at 5x

So as Forest Gump would say "That's all I have to say about that" LOL, my experience possibly worth exactly what you paid for it but the process is definitely working for me.

[DHuffman]

Im not saying reaming is not effective at eliminating donuts especially combined with turning. I'm saying I won't do it for the above reasons.

[bikemutt]

What might be helpful is if someone with a doughnut and a bore scope could post some pictures of what it looks like from from the inside.

[mnbogboy]

Thanks dave.. do you think the expander mandrel will push all of the doughnut to the outside the first time?

9
On fresh annealed brass the new bulletbitself will push the donut out somewhat. Once on the outside the geometry of the donut placement I believe acts as a fulcrum and internal case pressures tip the neck area inward constricting it somewhat which explains it tight after firing. With the donut there is poorer neck seal and a better chance for carbon buildup which may contribute to tighter neck mouth.if I was still working I should be able to replicate a donut situation and apply finite element analysis to the solid model. It would show where the stresses would be applied on the case itself.

[Windsage]

9
On fresh annealed brass the new bulletbitself will push the donut out somewhat. Once on the outside the geometry of the donut placement I believe acts as a fulcrum and internal case pressures tip the neck area inward constricting it somewhat which explains it tight after firing. With the donut there is poorer neck seal and a better chance for carbon buildup which may contribute to tighter neck mouth.if I was still working I should be able to replicate a donut situation and apply finite element analysis to the solid model. It would show where the stresses would be applied on the case itself.

Following this line of thought the slightly thicker area would act like an O ring at the base of the bullet.  This might lead to the bullet being able to wobble slightly as it begins forward movement.  This brings me to another thought.  One of the things we have always seen as a weakness of the bushing type sizing die is that it doesn't go all the way to the neck shoulder junction.  But looking at it this way, leaving the junction slightly loose might actually be helpful.

[CaptGrumpy]

Here ya g Grant. This will solve all your neck problems.

http://bulletin.accurateshooter.com/2020/11/the-most-advanced-neck-turners-blake-idod-and-autodod/

RABBIT HOLE ALERT! RABBIT HOLE ALERT!!!
Somehow I just knew that you would find another high dollar must have piece of machinery to sell us on!!! Nice find!!! But no!

[jvw2008]

RABBIT HOLE ALERT! RABBIT HOLE ALERT!!!
Somehow I just knew that you would find another high dollar must have piece of machinery to sell us on!!! Nice find!!! But no!

Some say ignorance is bliss. Maybe you just don't like to be informed?  ?
When I tell you it is a must have item, then you can assume I'm trying to sell you on it. Otherwise, I'm just posting stuff like that to keep folks current.

[CaptGrumpy]

Ignorance IS bliss!!!! I still inside ream those donuts out but fell in love with another of your high dollar gadgets! I will probably pick one up in a couple of years after I get everything settled and back up and running in Montana. I gotta get my reloading bench reset and start up my A&D FX120i V3 before I bang my head and find the V4 on my doorstep.
I have heard rumors of a 1000 yard rifle range east of Missoula and I am itching to get back on the range and dot some paper victims. I am loving life here but I sure am missing Range 12 back at Sacramento Valley. That range has spoiled me for life.

BTW does that reamer come with a mood light???

[jvw2008]

For the price it ought to come with a lounge chair, a six pack, and a movie.