Case prep before neck turning...?

[leoestby]

Hi, I have ordered a custom rifle in 7WSM and .316" tight neck chamber. So I need to neck turn my brass. But this is new stuff for me...

I have new unfired winchester brass. So what should I do before i neck turn them?

This is what I think I need to do:

1: Run them trough my Redding full body die (included in my Redding neck die set) to set all brass to same headspace length.
2: Use my sinclair expander die with the overzised mandrel (0,001" bullet hold)
3:Trim to the same lenght
4: Deburr the mouth slightly
5:Neck turn the hole lenght of the neck, not more than 0,0015" at the time. (carbide turning mandrel)
6: Clean up with 0000 steel wool

Please correct me if I'm wrong lol

 

[Deadshot2]

Re: Case prep before neck turning...?

If I were faced with this, I'd anneal first. Then use a die like the Forster Neck Size/shoulder bump die. Since the brass is new there should be no real issues with the body size of the cases and this die only works the shoulder for proper headspace. Use a bushing that gets the case mouth just a thou or so smaller than the expander die mandrel. I've stopped using the expander ball in any of my FL or NS dies in favor of a Sinclair Expander Die with OS mandrel.

Trim as you said then neck turn. It's a good idea to use a neck turning tool that has the proper angle on the cutter to cut back into the neck/shoulder junction slightly. This will prevent formation of the neck doughnuts that tend to form if one doesn't cut the neck far enough back. By cutting the very small amount from the shoulder that these cutters do gives a nice radius at the junction and prevents excessive metal flow into the case neck ID.

As for cleaning with steel wool, that's optional. If your're cutter is sharp and your technique uniform, the machined surface should look great enough.

As an added note, I've found that it's often necessary to do a second neck turn after the first firing. Since you need to do it for a custom chamber you don't have the same benefit as I where I can fire the case once prior to neck turning should I choose. When turning the second time, using the tool set exactly the same as when making the finish cut the first time around, one can reduce any buildup of metal that moves into the neck after the first firing. From there on it doesn't seem to be an issue, at least on my brass. I shoot .308 so there are different dynamics yet the principle's the same.

 

[leoestby]

Re: Case prep before neck turning...?

I have a redding neck die, and I'm not going to use the expander ball either. But is it important to use a bushing 0,001" under the sinclair expander die before I run it trough the sinclair expander die? Could'nt I bump the cases without a bushing?

Should I anneal also? I have the equipment, but did'nt know I had to :-O

Loots of questions... I't totally new for me Thanks for answering

 

[shoot4fun]

Re: Case prep before neck turning...?

The brass, if new, should be annealed well enough for neck turning. Maybe I don't do it right. I will run thru the neck sizer and expander die to make sure necks are round and fit snug on the turning mandrel first. Then I just turn them. How much will need to come off total? Take it off in two or three passes in equal amounts. 7WSM necks are really thick. I would do the rest of my prep once the brass is turned.

 

[427Cobra]

Re: Case prep before neck turning...?

I do the following
FL size with a non bushing Forster FL die with the expander ball removed.
Expand with the expander mandrel.
Trim to a unified length using my Giraud Trimmer.
Clean out any chips from trimming.
Turn my necks to .0145, this just hits the high spots on Win 7-08 resized to 260.
Tumble lube off(Imperial Sizing Wax)

I use a 21st Century Shooting turner.

 

[BK7saum]

Re: Case prep before neck turning...?

Use a FL size die not a bushing die. A bushing die will not size the neck shoulder junction. On new brass maybe not too much of a problem but on fired brass that is sized a bushing die leaves the id and od at the neck shoulder junction a little larger than the rest of the neck id/od. If you then turn that the neck shoulder area will have a slightly thinner area than the rest of the neck.

 

[Deadshot2]

Re: Case prep before neck turning...?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BLK7</div><div class="ubbcode-body">Use a FL size die not a bushing die. A bushing die will not size the neck shoulder junction. On new brass maybe not too much of a problem but on fired brass that is sized a bushing die leaves the id and od at the neck shoulder junction a little larger than the rest of the neck id/od. If you then turn that the neck shoulder area will have a slightly thinner area than the rest of the neck. </div></div>

This doesn't seem to be the case with my Forster Neck Size/Shoulder Bump busining die. When I size, there is a small line of lube left on the case and it goes right into the shoulder/neck junction. To me, no apparent difference than a FL sizing die. Don't know about any of the other bushing dies, just use the Forster die like this

Neck Size/Shoulder Bump Die

This die can also be adjusted so it bumps the shoulder for proper headspace but also leaves a small unsized portion of the neck to help center the cartridge in the chamber.

 

[BK7saum]

Re: Case prep before neck turning...?

OP said he had a redding neck die. My experience with the redding is that it leaves a small amount unsized near the shoulder. Not much but do you want a thin spot at the base of the neck.

I'm not familiar with forester bump die.

 

[leoestby]

Re: Case prep before neck turning...?

Hi. I have now orderd a FL forster die, 40degrees cutter on my neck turner (I saw that I touched the shoulder before I was finished with the neck) and a wall ticknes micrometer.

I have annealed my brass, so next step will be to run it trough the forster die to set correct headspace. (also make sure the expander die will have contact with the whole area of the neck. Some dents goes "out" and not in, so I think its a good ide to run it trough a non bushing die before i use the expander die.


Thanks for good help all of you!

 

[BK7saum]

Re: Case prep before neck turning...?

You're welcome. Sounds like you're on the right track.. good luck.

 

[Deadshot2]

Re: Case prep before neck turning...?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BLK7</div><div class="ubbcode-body">
I'm not familiar with forester bump die. </div></div>

Check it out. I find it to be extremely versatile. Use it like a "body die" but bumping the shoulder back only, no sizing to the main case body. Partially neck size if desired. Can be used with an optional expander ball if you want to bump/neck size, expand, all in one process.