neck turning

[bobby]

Hi,
Could you help me please.
What is the correct way to neck turn new cases.
Should you neck turn them as they are as new or should you full length size them first then use an expand mandrel in the neck to smooth and slightly expand the case neck,then turn the necks to the size you want.
I will be using the K & M microadjustable neck turner and mandrel.
If the chamber is for a 6xc and the chamber neck size is .272,I want a tight neck)What size at the neck should I have for a loaded round.
Thank you for your help.

Bobby

 

[Forum Boss]

Bobby,

You can call Ken at K&M and he'll give you the specific procedures for his tool which adjusts cut depth differently than most other tools. Do read his instructions first.

Ken Markle @

K&M Services
Carbide Neck-turners, Arbor Press, Case Prep Tools
5430 Salmon Run Road
Dover, PA 17315
Phone:,717) 292-3175

Here is an article you should read: http://www.6mmbr.com/JGcaseprep.html

Here is a Benchrest.com thread pertaining to the K&M tool: http://www.benchrest.com/forums/archive/index.php/t-8980.html

Yes you should full-length size first, trim all cases to the same length, and use the K&M Expandiron before sizing. It is important that all cases be the exact same length. The appropriate Expandiron should give you the correct inside diameter to use the K&M mandrel on the neck-turning tool.

For a .272 chamber diameter, we would go no larger than .270 on a loaded round for .001" clearance per side. More clearance is not a bad idea--many shooters prefer .003-.004 over a loaded round. Some short-range benchresters go as low as .0005" per side, but that can cause issues.

 

[mikecr]

Buy extra brass, cuz it'll take a few to get setup. To get a feel for cutting and best feed rate. Then theres the issues that you'll need to overcome related to the expandiron and brass springback. Use a standard feeler gauge for a close setting, and tweak it in a bit at a time till dead nutz. I assume you have a neck thickness gauge. I use a dab of Mobil1 on the turning mandrel, but alot of lubes work.
If reasonable,<.003), I turn in one pass to final thickness desired. Feed at a consistant rate and back off very slow to peel off any record grooving. Let the tool cool if hot and clean before next case. I run the turn up onto the shoulder 'enough' and have never concerned myself with case length, neck length, or sizing,outside needed neck expansion). Those are different steps in case prep.
I use the Sinclair system now. Their mandrel system is superior in my view. But the K&M has a great adjustment system. Just a little tricky to learn.
Check each completed neck thickness before going to the next,you want to catch issues early).

 

[Aussie_bob]

Have i missed something here? This is for a 6XC which is 6mm or .243" and you have a chamber of .272" which is a difference of .029" so .0145" neck wall thickness so set your cutter to give you a .013" neck wall thickness and you will probably end up with .001 clearance around the neck of a loaded round.
But i dont think i have seen brass with .014" neck wall thickness so at .013" you should hardly be skimming the neck as .272" is usually a no turn neck.
Or have i been without sleep for too long and missed something here.

 

[Vulcan]

I am with Aussie on the .272 neck. I don't think you even have to turn at all unless you just want to knock off the high areas of the neck. I have new unturned Laupa brass so I went an seated a bullet to see what the neck would measure. It came out to .270 so with a .272 neck, I don't think I would take the time to turn the necks.

 

[Aussie_bob]

If you are using a bushing type die i would at least skim the necks so that you will have uniform neck tension.
But if you are using expander ball type for neck tension dosen`t really matter.
Since getting into more precise shooting i have found neck tension consistency is needed so by skimming the necks and then getting the correct bushing you can either have .002" or .003" neck tension or what ever you find is the best for you.
In my 30BR i run a .330" neck chamber so turn my brass so i have a .010" neck wall thickness so a loaded round neck is .328"which gives me .001" clearance. .002" neck tension seems to be ample have tried .003" but don`t think i need it.
After fireing with spring back i could reload with out redoing the neck and still have enough neck tension to hold the projectile in place,
Mainly because it sits right on the powder column and cant slip in if bumped, but the point is i am hardly working the brass so should get long life.

 

[StephenPerry]

Bobby
For neck turning what I recommend is buying a Sinclair Mandrel Die, you can buy additional mandrels later if need for the sme die. All that is needed is to pull the neck to conform to the mandrel on your cutter. By pulling the neck you make the neck concentric to the turner mandrel. There is no adjustment here. lube the mandrell on the pull die and what I do is push in/pull out a nylon RCBS brush on a hand tool. The nylon brush smooth out and coat the dry inside neck with lube ftom the previous case. Lube the brush on the first case. Imperial Sizing Die wax for all the turner operations but others work fine too.
Now with concentric necks set your turner for a half diameter cut. Run the cases on to your lubed mandrel and turn clockwise slowly so as not to tear the neck. Ay half diameter you should have no accidents. Set your tuner to cut into the shoulder but only get full use of the radius on the cutter. Back out once you cut into the shoulder at the same slower rate clockwise. This only your first cut so a faster cut will not harm. Brush the chips off and adjust your trimmer for your desired bullet in diameter. You have taken off a good amount of the neck material so your next cut will get you close to what I recommend a thou clearance on each side of neck bullet in. Or in bushing terminology a .270 bush for a .272 neck chamber. Run your cases after lubing again for the second cut. Brush off scraps. Now some stop here but I recommend a third cut. This time you will be doing a skim cut. Leave your turner setting on the second cut and turn your necks one last time. The third cut could take or .0005 or less but leaves with a perfectly smooth neck to your dimension. Pat yourself on the back you are now an expert at one form of reloading. Let it be Said Let it be Done.
Stephen Perry

 

[Cheechako]

Bobby

Not all 6XC brass is created equal. If you have a .272 chamber neck you may have a hard time getting tight neck cases with some generations of 6XC brass. Some of the earlier ones had a no-turn dia of .269 and taking a clean up neck turn cut left you with .268 or so. Most of us used a .270 chamber neck.

So, bottom line is, check everything before you invest in brass and/or start turning necks.

Ray

 

[bobby]

Thank you for all your help.
Bobby