donuts in 223 Lapua brass ?

[CharlieNC]

Necks are thinner on LC brass vs Lapua which can play into the differences in behavior, and a lot of considerations as to how.

 

[mikecr]

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.

This is not true (either) in a broad sense.
Heavy FL sizing does move brass, thick toward thin, right up cases into shoulders, neck-shoulder junction, necks, and onto your bench after trimming.
It is not shooting that moves brass like this. It's sizing.

I can say this because my 26wssm Imp cases, which were initially neck turned and have never been body/neck sized with a die, have 80+ reload cycles on them with no donut formation. In fact, there have been no changes whatsoever. And this is right at a SAAMI max load, 65Kpsi.

It's when you run a 6PPC at competitive pressures that flow can occur. But that's a tiny case, and those pressures are not viable in anything larger.

 

[big5ifty]

... my 26wssm Imp cases, which were initially neck turned and have never been body/neck sized with a die..

How do you size them ?

 

[mikecr]

How do you size them ?

My chamber is 'fitted' to new (but neck turned) brass, and forms 35deg shoulders by 3rd firing.
Then around 9th reload cycle, and every few after, I nudge shoulders with a custom bump die.
No neck or body sizing

My intent now is to try either 60deg shoulders or HEMI, to see if I can remove bumping for good.

 

[big5ifty]

I nudge shoulders with a custom bump die.
No neck or body sizing

Was this custom bump die made to the spec of your fired brass ?

If you don't resize the neck, how are you managing to keep the bullet seated ?

 

[mikecr]

The bump die was made from brass which I had taken beyond SAAMI max.
The die body interference is ~0.0002" of brass, to hold brass with no sizing.
That took it from body die to bump die.
The chamber neck is ~1/2thou over loaded, and with necks turned to 13thou, the necks do not upsize with firing, and fully spring back. They're always ready for re-seating, and never need annealing.
The entire chamber is fitted for this plan, and works that way.

There is more to it than filling out a reamer print though.
I put enough barrel steel around the chamber, coned breech support, and the single shot action loading tray is machined for the cartridge. It's CRPF, standing blade ejection. With that I get perfect feeding, and no extraction problems with SAAMI max loads. It's a one-off BAT magnum action.

I'm thinking about exploring further with a customized BAT SV.
I wanna see if I can run 6PPC competitive pressures with a 260 Hemi, with no sizing and never replacing cases.
My 26wssm Imp matches capacity of 260ai, with way thicker brass, but the 260 is smaller diameter,, so who knows.. I'll go until I stop learning.

 

[big5ifty]

They're always ready for re-seating, and never need annealing.

You've put together a system that never needs trimming, sizing or annealing, effectively bypassing the most time consuming aspect of reloading, completely eliminating the brass variable from the equation.

Why is this not big news ?

 

[mikecr]

Why is this not big news ?

It's heresy.
You should just do what everyone does (for ~100yrs or more), as it's the easiest path to good enough.

 

[rebs]

what about only using a LCD to size the neck ?