Neck Turning

[oneokie]

Would like to draw on the knowledge and experience of the good people on this forum.

When turning the necks on straight wall rifle cases, what is the minimum wall thickness that is necessary for a case life of more than 1 firing? Would .0075" -.007" be too thin?

(have some cases with .008" walls now, but want to try a boolit that is .001 larger than what I am now using)

When turning, is it better to do so with cases that have not been annealed?

Would this be a good way to achieve desire results--
Make a mandrel of the desired boolit diameter, insert mandrel into case to the depth of the seated boolit, then turn the OD to the desired diameter. (lathe)

[Scrounger]

Personally I'd like to keep all the brass the factory gave me there, in which case the only thing I'd turn the brass for is to make it fit the existing chamber more correctly, maybe 2 thousandths expansion room.

[Bass Ackward]

When turning the necks on straight wall rifle cases, what is the minimum wall thickness that is necessary for a case life of more than 1 firing? Would .0075" -.007" be too thin?

When turning, is it better to do so with cases that have not been annealed?



okie,

Minimum thickness is hard to describe. The anneal means a lot here as does your tool sharpness, cutting speed and cut depth. If I was going to attempt this, I would leave the brass as purchased, turn to spec, then anneal. And the mandrel method is as good as any. Just indicate it up and true the mandrel with a light cut before beginning so it is running dead nuts. You can't afford to lose anything when you are running that thin. IMO.

[HORNET]

FWIW,I've got a bunch of Remington Hornet cases that only have .0060" neck thickness. Had a heck of a time finding dies that would size them small enough to hold a .224" slug. Crimping, of course, would seem pointless on such a thickness. I use a Forster neck turner for other cases which does OK, but is a pain to duplicate settings with. You might want that mandrel somewhat longer than the anticipated seating depth for greater flexibility. Keep your tool sharp, brass is tricky to cut. Good luck.

[leftiye]

Plus one on the forster outside neck turner. Maybe not any more (and yes maybe still) but it started life as a benchrest item, and does a fine job. Probly more accurate than a lathe is my bet. 32-20 brass is .006 and that's all the thinner I'd go, don't like that none. .008 is still thin. If you're messing with a big bore, uniforming case necks doesn't do much for accuracy (30 and up).

[monadnock#5]

Outside neck turning works best on brand new cases. Work hardened cases are much more difficult to work with, and are hard on the cutting tool. After touching off on a work hardened case, you might have to set your tool for a .003 cut to remove .001 of material. You're bound to ruin a number of cases before you figure it out. If you have to use fired cases, anneal some of them and try it both ways.

As for a mandrel, size your cases first, and turn your mandrel to the same size as the expander button in your sizing die.

[S.R.Custom]

Would be less of a PITA over the long run to open the chamber up a bit...