Necking down

[Bertram]

Have justed started loading for 22-250 AI and got to thinking about another project similar to 224 stark cartridge.
The question I have, is there a general rule of thumb about how much to neck down in steps, e.g if I was to neck down a .308 to .224, how many steps should I take?

[Terry Balding]

It depends on your equipment and process. With standard dies I would full length size the brass, neck turn it, and anneal it. The I would reduce the neck diameter by no more that .020 per step.

Example .308 to 7mm(.284) to 6.5mm(.264) to 6mm(.243) to .224.

Terry

[82boy]

Again like mentioned it depends on your equipement, but every step ou make will add to the run out on the cartridge, but then when you fireform it with 50,000 PSI it should straighten it all out. I try to neck up/down with the least amount of steps. You have to watch it if you take to much in a step you will push the neck down into the shoulder, and trash the brass. I personaly would ty to do it in 2 steps, from 308 to 6.5, then to 22.

[gotcha]

Bertram, Welcome! Don't think there is any "rule" for reducing nk. size. My results will vary w/ wall thickness of brass more than anything. Removing the expander ball will reduce work hardening if reducing in more than one step. I've created 22/250 brass from 250 Savage in one step (.033" reduction) & no problems. If you're making a drastic reduction in nk. size always good to chk that loaded round fits nk of chamber.............. So, that would be a "rule" ;D

[Apache]

If you try to reduce too much at one time it'll be obvious. ;)

As was said pay attention to neck thickness when finished reducing. Will be dangerous if it's bigger than your chamber neck area.

[Bertram]

Many thanks for the feedback guys, I have been reading a few books on the subject and they all seem to say the same info.
So far I have shortened a .308 winchester die and did some experimenting necking down .44 magnum brasss to .308.
They mostly took rough form but crumpled the necks so I annealed the cases and was surprised to find they would then neck down smoothly with one pass to .308 diameter, which made me wonder how far I could then go to get to .224.
I think the next step will be to 7mm then to .257" and on to .224, possibly with another anneal on the way.
I did also find that having the expander in the die crumpled necks as well after annealing.

[gotcha]

Yep, the annealing part can be touchy. Easy to get brass too soft. Also easy to under anneal. Have you tried Tempilac to establish correct temp. for annealing?.......... I'm red/green color blind & had a heck of a time trying to interpret color of annealed brass. The tempilac got rid of my guess work & gave me much more consistent results.

[handirifle]

When I first started reloading for my 243, I used to regularly neck down 308 brass I picked up at the ranges. This was back in 1973, and I knew nothing about annealing then. I used to do those in one pass, and almost never lost brass. If yo see how cases are first made at the factories, you become amazed at how far the machines can stretch that new brass.

[Joe O]

You may be able to reduce by .020 per stepdown,but thin brass will buckle the shoulder half the time.I've been necking down 218 Bee brass to 20cal,and found a intermediate step of .230 worked much better,before the final .220 neck bushing.

[helotaxi]

you become amazed at how far the machines can stretch that new brass.
The thing is that is NEW brass. The stretching work hardens it making it more rigid, but also more brittle and likely to do something that you don't want it to when you try ot stretch it further. Annealing the neck makes that part of the brass new again.

[Bad Water Bill]

I was talking to a friend about sizing 30-06 down to 6.5-55 without much case loss.

He had a different answer than I have ever heard before.

When you down size do each stroke VERY SLOWLY.

Jim was loosing about 50% using normal speed, now it is down to .02%.

How slow is slow enough? Every press is different so you will have to experiment. Should not take more than 8-10 to get you on track.

[Aircraftmech76]

I have made a couple 6.5x47 Lapua cases from Lake City 308 brass in one step. I first trim the required amount off the 308 case, and then run it in my Redding body die. I have yet to damage a case, and the shoulders look factory.

Kevin

[GaCop]

I have made a couple 6.5x47 Lapua cases from Lake City 308 brass in one step. I first trim the required amount off the 308 case, and then run it in my Redding body die. I have yet to damage a case, and the shoulders look factory.

Kevin


Just for grins I did the same thing using RP brass and had the same results.