Donuts- inside ream or turn the necks?

coyoteking

coyoteking

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I’ve got the dreaded donuts. These are on 22-250 Lapua cases that have been fired 3x.

I size with a Redding body die which is set to bump the shoulders 1-2 thousandths. I then size the necks with a Lee collet die.

The other night I was sizing some cases and I noticed that when I lowered the mandrel into the case neck I hit some serious resistance right at the neck/shoulder junction. It took a fair bit of force to push the mandrel past this choke point. I stuck my bore scope into a few cases and can clearly see a donut.

I’ve never gone down the neck turning/reaming rabbit hole yet so I’m in need of some advice. I just purchased a Forster trimmer with the neck turner from a fellow nutter. I’ve also got a .224 Forster neck reamer in my possession.

What’s the best way to get rid of these infernal donuts?
 
I've had great results from my Forster inside neck reamer. It attaches in place of the trimmer pilot and reams the donut out at the same time it trims the brass. I really only turn necks when the brass is new, and then just ream out the donut when it starts to build up. Only trick is you have to do it before sizing.
 
coyoteking said:
I’ve got the dreaded donuts. These are on 22-250 Lapua cases that have been fired 3x.

I size with a Redding body die which is set to bump the shoulders 1-2 thousandths. I then size the necks with a Lee collet die.

The other night I was sizing some cases and I noticed that when I lowered the mandrel into the case neck I hit some serious resistance right at the neck/shoulder junction. It took a fair bit of force to push the mandrel past this choke point. I stuck my bore scope into a few cases and can clearly see a donut.

I’ve never gone down the neck turning/reaming rabbit hole yet so I’m in need of some advice. I just purchased a Forster trimmer with the neck turner from a fellow nutter. I’ve also got a .224 Forster neck reamer in my possession.

What’s the best way to get rid of these infernal donuts?
Click to expand...
I might not understand the issue - I no longer ream necks - my rifles could not show any difference in group size, when I did so. I believe, however, that there are barrels / chambers that will respond to that - I do not own any, at least those that I tried it on. As was posted, if you re-size the brass, there is no "donut" inside - the neck expander will have made the inside the correct size for the bullet of choice - so, if there is a "lump" it will then be on the outside of the neck - at the shoulder junction. At that point, inside neck reaming won't do anything.

I do not crimp any jacketed bullets in centre-fire rifle loads - so my "neck tension" is all about the inside neck size, compared to the bullet size. Richard Lee's "Modern Loading" book suggest you want no more than circa 0.002" tension - any more than that and you are going outside the elastic stretch ability of the brass - so sizing "smaller" actually makes for less tension - because setting the bullet will expand the brass, rather than stretch it. I do not really understand how an inside reamer can be made so precise to work, although I suppose they can be made similar size to an expander ball. But some people will polish an expander ball to make it a smidgeon smaller for their purposes - I do not think that can be done with a reamer, by "normally equipped" people.
 
Potashminer said:
if you re-size the brass, there is no "donut" inside - the neck expander will have made the inside the correct size for the bullet of choice - so, if there is a "lump" it will then be on the outside of the neck - at the shoulder junction. At that point, inside neck reaming won't do anything.
Click to expand...
IF that were the case, maybe, but resizing alone doesn't get rid of the donut completely

partial neck sizing seems to be the best choice
 
coyoteking said:
I’ve got the dreaded donuts. These are on 22-250 Lapua cases that have been fired 3x.

I size with a Redding body die which is set to bump the shoulders 1-2 thousandths. I then size the necks with a Lee collet die.

The other night I was sizing some cases and I noticed that when I lowered the mandrel into the case neck I hit some serious resistance right at the neck/shoulder junction. It took a fair bit of force to push the mandrel past this choke point. I stuck my bore scope into a few cases and can clearly see a donut.

I’ve never gone down the neck turning/reaming rabbit hole yet so I’m in need of some advice. I just purchased a Forster trimmer with the neck turner from a fellow nutter. I’ve also got a .224 Forster neck reamer in my possession.

What’s the best way to get rid of these infernal donuts?
Click to expand...
Well the first question I would ask is does it matter. Are you seating deep enough that it is a concern?
 
boxhitch said:
IF that were the case, maybe, but resizing alone doesn't get rid of the donut completely

partial neck sizing seems to be the best choice
Click to expand...

I watched that video last night. One of the best shooting YouTubers out there, he explains things so well even a dummy like me can understand it.

After a bit of researching I see that I can use my Lee collet dies to partially size the neck by using a washer as a spacer between the shell holder and the base of the die. I’m going to try this method first, if it works and doesn’t induce runout on my cases then I think it will be the best solution.
 
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