Neck turning issues


Well-Known Member
Mar 31, 2009
hey yall,

i have a forster neck turner and im needing to turn brass for my 6mm Hagar.

i have it set up correctly it just barely nicks the shoulder and only turns one side of the neck off and all the regular "touch up" stuff...

but, while say 6 out of 7 come out a perfect .268.... sometimes it turns one way down the like 264 fr no apparent reason.....

i f/l resize just before turning. but i dont use and expander... is this maybe the problem?

no the tool doesnt move... its red loc-tited in place and i have even tried it out on some worn out 6 br brass and its true to form.

what the heck is going on?

What is a 6mm Hagar? Does it have a .268" neck? What is your loaded diameter?

An expander (not the sizer ball) before turning is always necessary for consistency. Buy a Sinclair. There are many forums to consult about neck turning. Spend some time reading those before you continue.
When I turn new brass, I use an expander to straighten out the neck. I don't run the brass through a sizing die, makes the mandrel too tight. Sounds like the neck wall thickness on some of the brass may be to blame.
The necks are about 2705 after turning just to clean up.
What I don't understand is how a tool set firmly in place can cut deeper.

How do I buy an expander?

What specifics should I need before ordering?
It's either the tool or the brass. How are you measuring the necks? I use a micrometer made for measuring neck wall thickness. Sinclair International has all kinds of reloading tools. The mandrels and expander die come in many sizes, order what you need. BTW, the manderals also fit the neck turning tools. Check them out at
Got one comin thanks.

I measure neck wall thickness and O.D. with my tools from Sinclair.
If you measure neck wall thickness, then you should know what it is.
You said some necks come out .268, some .264, and some .2705.
That means nothing.
What are the thicknesses coming out like?
Or, when you seat bullets into these necks, what are the loaded OD measurements?

Whenever turning you need a matching system. That is turner, cutter blade, turner mandrel and matching neck expander. I don't know if Sinclair's expander will result in proper fit to a Forster turner mandrel after a neck is expanded & sprung back. It might.
I have te thickness written down I'll check Friday when I get home. Necks are 2705 loaded on the rounds that I turn down to 269 and size with a 268 bushing.

These are just the "good" ones. About six out of seven. Then there's those that turn down to 265 when I turn them.
I used to use the oversized expander, but not anymore. I polish the mandrel down to where it's about a half thousandth to a thousandth under the neck ID. Then I run the cases thru a full length die again just to be sure. I use powdered graphite for a neck lube in the I'D. But before I cut the first shaving, I sort the cases. You may find some neck O.D.'s that are undersized and yet some that are somewhat oversized for what ever your looking for. Ideally you want to shave a max of about .004" to .005" total, but dosn't always work that way. If I have to remove more that six thousandths, I like to make it in two cuts (just works best for me) as I seem to get a better finish on the brass. I also like to leave about three to four tenths on the neck O.D. to polish off with a Scotch Brite pad. Lastly, for a finish cut I prefer to do it the hard way; by hand. I will rough the necks with a B&D electric screw driver
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