Which Redding Neck Bushing?

[Gollum]

The 30BR project is coming together! I have a Redding 7BR type S FL sizer ordered, but didn't order the neck bushings yet, because I don't have a clue what size to get.

The gunsmith just reported that the neck measures 0.3325"

What bushings, or range of bushing sizes should I order?

Also rdered Lapua 6BR brass to neck up to 30 cal, along with a K&M neck turner - how do you determine how much to turn off the necks? I'm assuming you take 0.3325-0.308 = 0.0475" and do something with that figure?

 

[Aussie_bob]

Ok with a chamber neck size of .3325 you would want a loaded size of .330 which will give you .0025 clearance so you take .308 from .330 which gives you .022 so you can have a neck wall thickness of .011 so get a feeler gauge and set turner and set at about .015 turn off the donut up near the shoulder neck join then when you have all them done set the cutter down to either .013 and do it in two cuts or go straight to .011 and do it in one cut.and the neck bushing would be .328 which will give you .002 neck tension. think i have that all correct if not someone will point it out i am sure.

 

[Gollum]

Thanks for the help!

I noticed a stupid math error in my origional post. 0.3325"-0.308" = 0.0245" NOT 0.0475" Duh.


What do the necks start at? I'm assuming that I won't be turning much off to get a neck thickness 0.011"

 

[Aussie_bob]

Mate to be honest i don`t know what they start out at. I have just turned 100 and don`t know, hows that. I will go measure one i havent necksized yet.
Ok just measured a few at random and looks like about .015 to .017 thats the neck wall thickness of the 6mmBR brass before neck expansion so when you have expanded and get the donut just set the cutter up to the thickness of the neck as is and turn the donut off and then work from there should only have to turn off about .003 so the neck of your loaded brass ends up at .330 which gives you .0025 clearance for it to expand to release the projectile.