donuts in 223 Lapua brass ?

[rebs]

This is for a Tikka T3x 223 bolt gun only.
Can donuts be avoided by neck sizing with LCD and then body sizing ?
Can donuts be avoided by only sizing one half the neck with a Redding bushing die ?
Why haven't I had donuts with Lake City 223 brass full length sized ?

If I load bullets longer to avoid the donut it changes the distance to the lands and throws the load off and doesn't leave much bullet in the neck, so how do you compensate for this ?

 

[mikecr]

Initial donut area thickness is inherent to brass manufacture.
Upsizing necks, or heavy FL sizing builds thicker donuts.
There is no regular neck sizing that causes donut thickness change.

It's avoided by not seating bullet bearing into it.
If you have to seat so deep, then you could neck turn or ream.

 

[big5ifty]

Why haven't I had donuts with Lake City 223 brass full length sized ?

Lake City brass is probably harder [ different alloy composition ] than Lapua, so it doesn't flow as easily.

You can do two things -

1. seat the bullet long to avoid the donut
2. ream the case neck to remove the donut

And in your case, you could also stick to Lake City brass.

Neck turning, in my experience, is for when the donut is on the outside and interferes with chambering.

 

[rebs]

Thanks for the replies

 

[urbanrifleman]

Use the expander ball?

 

[ronemus]

Neck turning, in my experience, is for when the donut is on the outside and interferes with chambering.

If you use an expander, whether a mandrel or an expander in the sizing die, the donut is moved to the outside of the neck where it is easily removed by neck turning, Internal reaming is more problematic as the reamer diameter must be matched to the ID of the sized neck, and that's a moving target as the brass changes with each firing.

 

[big5ifty]

If you use an expander, whether a mandrel or an expander in the sizing die, the donut is moved to the outside of the neck...

In my case, I necked up 7mm RUM to .375, the donut formed on the outside at the old neck-shoulder junction after a couple of firings.

In my .243 brass, using a sizing mandrel does not move the donut to the outside, I had to ream the necks.

 

[pilediver]

I shot some barrel break in rounds of 6 BR yesterday, Norma brass 6 times fired.
Resized with a redding small base full length bushing die, only partially sizing the neck, then run over a mandrel for final neck sizing.
Fired the brass
The fired brass will accept a bullet until the bullet reaches the donut inside the neck
Using the mandrel did not move the donut to the outside of the neck
The only way I see to keep using this brass is to seat bullets above the donut, or inside ream the necks

 

[mikecr]

Have you thought that through?

For a reamer to work, without munging up the entire inside length of necks, and still getting the problem donut thickness, the neck ID would have to be just a smidge over reamer diameter (consistently).
Since it would be a miracle for that condition, you would likely have to order a custom reamer.

I outside turn necks for every cartridge (of mine), 22-26cal, all kinds of initial thicknesses, never had a problem getting donut thickness out for good.
It is always best to do this with NEW brass. If you try it with fired brass, you'd need a miracle again.

 

[pilediver]

So I will just seat the bullets above the donut, like I have been doing.

 

[rebs]

So I will just seat the bullets above the donut, like I have been doing.

How do you find the best seating depth for accuracy when you are limited to seating above the donut ?

 

[Kracken McGraw]

How do you find the best seating depth for accuracy when you are limited to seating above the donut ?

For 69 grain bullets and smaller you should be above a donut anyway. Tune as normal.

 

[pilediver]

Start at jam and work your way out

 

[rebs]

For 69 grain bullets and smaller you should be above a donut anyway. Tune as normal.

what about the 77 and 80 gr

 

[Kracken McGraw]

Are you getting donuts in your Lapua brass?
The easy way if you have a regular sammi chamber would be just to get a Forster FL die with expander ball, this should pull any problem out to extra length on brass to be took care of by a trimmer.

 

[mikecr]

The easy way if you have a regular sammi chamber would be just to get a Forster FL die with expander ball, this should pull any problem out to extra length on brass to be took care of by a trimmer.

All even worse than a donut
The easiest thing to do is NEVER FL size necks.
Let donut thickness blow out & stay out to the chamber neck.

 

[Kracken McGraw]

All even worse than a donut
The easiest thing to do is NEVER FL size necks.
Let donut thickness blow out & stay out to the chamber neck.

?

 

[prone.life]

good vid on donuts from Keith Glasscock of Winning in the Wind on youtube; i stopped inside neck reaming after watching this, so happy i went this route. tldr = use a bushing style fl sizing die

 

[grovey]

I'm on the same page as Kracken... I skim the neck to clean most of it up, and take a little bite outta the shoulder when the brass is new. From there it's FL size with a Forster die. No donuts problems in my Tikka 223's.

 

[Webster]

This is for a Tikka T3x 223 bolt gun only.
Can donuts be avoided by neck sizing with LCD and then body sizing ?
Can donuts be avoided by only sizing one half the neck with a Redding bushing die ?
Why haven't I had donuts with Lake City 223 brass full length sized ?

If I load bullets longer to avoid the donut it changes the distance to the lands and throws the load off and doesn't leave much bullet in the neck, so how do you compensate for this ?

The way you size should have no effect on the formation of donuts. Shooting causes the shoulder to flow forward. I doubt that sizing makes the shoulder flow forward. Sizing the neck should have no effect on the formation of donuts. In 45 years I have never dealt with donuts because my bullets are only seated about half way down the neck. Some basement scientist will say donuts change the flow of gas. Never even looked for donuts in my 6BR or 6BRX. My 6BR has shot a few groups in the 1s, most groups under .4". Good enough for my needs.