Necking down, what do you do?

[Hookturnr]

Hey guys, I've got a pile of odds n ends 30.06 brass I've kept around for a while but only one 30.06 that sees nothing but nosler custom brass.
However, I have a couple 25.06's

so I figured I could neck down all that 30.06 to 25.06.
I took a couple cases, lubed 'em up and shoved 'em in that tight little hole and BAM!

out came a 25.06! Albeit it was a little long but everything measures up otherwise.
So, I am left wondering what you guys suggest be done with these once they are trimmed up? Haven't been able to find much on the topic but have heard you should/shouldn't anneal before first firing in different places. So what do you guys do?

 

[Jeffvn]

Re: Necking down, what do you do?

necking from 30 cal to 25 cal in one move is going to be very tough on the brass. not necessarily impossible, just make sure you are very well lubed when you start the process.

I once took 308 and necked them down to 243 as an experiment. I did it in about 5 steps with a .308 neck bushing die. When I got to the final destination (.243) I used a neck bushing full size .243 die. I annealed at .243 before I ever would have fired a shot. Probably should have annealed it at 6.5 on the way through, but knew I was going to do it at .243.

Annealing the brass does not hurt anything and eliminates the work hardening from the sizing process. I anneal all my brass frequently.

Jeffvn

 

[bohem]

Re: Necking down, what do you do?

Check the ID of the neck, likely you'll need to neck ream (I did when I ran 30-06 down to 6.5-06's)

Otherwise, Jeff's advice is pretty complete, he certainly knows his shit when it comes to hitting things from a long way off.

 

[Clark]

Re: Necking down, what do you do?

8x57mm->7x57-> 257Robers works well.

The wildcat handbooks will say no more than 10% per step.

 

[former naval person]

Re: Necking down, what do you do?

Do load a bullet and measure the outside diameter of the loaded round versus a fired case from that rifle. Necking down usually thickens the neck and you may not have clearance for expansion of the neck to release the bullet...which can severely drive up the chamber pressures and velocity/accuracy variations. The sized down cases may need neck reaming or turning to get the required clearance. Depends upon the cases and rifle.

 

[flashhole]

Re: Necking down, what do you do?

This may be helpful. Anneal your case neck and shoulder before you down-size and it will go smoothly in one resizing step. I do it all the time with military brass.


http://shootersforum.com/showthread.htm?t=43210&highlight=flashhole

 

[shoot4fun]

Re: Necking down, what do you do?

I used to form 25-06 from 30-06 brass and did it just like you did. I, fortunately, saw no ill effects from doing it. That doesn't mean you can't run into the issues mentioned above so do it with care.

 

[Clark]

Re: Necking down, what do you do?

The necking down to watch out for is 308 -> 260 or even worse, 308-> 243.

Even in a sloppy SAAMI chamber, that can pinch a neck. And pinched necks make pressure spikes way out of proportion to what is intuitive.

 

[264highlandhunter]

Re: Necking down, what do you do?

To make my .256 newton brass I run 30-06 lapua brass deep into a 270 sizer, then into my newton sizer and trim. If you use too much lube you will krinkle the shoulder every time. Its a labor of love for sure.

 

[Hookturnr]

Re: Necking down, what do you do?

Thanks for all the info!
I read everything I could find at the time before I decided to go ahead with it and was aware of the possible neck thickness issues. I checked the O.D. of my necks after sizing down and they are 0.005-0.008 under a fired case dimension so I think I'll be alright. I'll check the O.D. again after I load a bullet to be sure though.
I was really wondering about the annealing most. I took 15 cases and ran them as my test batch and had no issues making the change in 1 step. I just made sure they were well lubed and had no issues. I think I'm going to try annealing half of them now and half after fire forming to see if I can find any difference. If I do find myself having to turn the necks down that's going to be a whole new project but we'll get into that later on.