neck terning

col48 · #1 05-03-2006, 04:09 AM

Hi all

I am trying to decide whether to neck tern my 270 brass or not.
I have a 270 wsm lilja bbl minimum sammi speck chamber.
I have Norma brass.
Now i am thinking of getting my bushes for the redding comp die,it is a full custom rifle.Do i need to neck tern with that speck chamber,or would you leave the brass,
Or i could take of 80% and uniform them.
The reason i am asking is when i neck terned my last 270 wsm cases for a factory rifle,And then shot some that had not been done,the non neck terned ones shot the best.(But this was a factory stick)
So what do you lot think.

And how much neck tension would you start with for a rifle with a mag.

Thanks for the help
Colin

Ballistic64 · #2 05-03-2006, 06:51 AM

If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber?

col48 · #3 05-03-2006, 10:01 AM

[ QUOTE ]
If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber?

[/ QUOTE ]

no but may be nesika will,they built the rifle

Bart B · #4 05-03-2006, 10:26 AM

If your case necks don't vary in thickness by more than .001 inch, neck turning usually isn't needed. Either way, your cases will center at the front of the chamber when the firing pin drives them hard into the chamber shoulder. As long as your sizing die leaves a case with a straight neck, that's fine.

I'd use a bushing .002 or .003 inch smaller than a loaded round neck diameter. Depending on how much spring back the necks to, the bushing .003 inch smaller one may be best.

col48 · #5 05-03-2006, 10:34 AM

[ QUOTE ]
If your case necks don't vary in thickness by more than .001 inch, neck turning usually isn't needed. Either way, your cases will center at the front of the chamber when the firing pin drives them hard into the chamber shoulder. As long as your sizing die leaves a case with a straight neck, that's fine.

I'd use a bushing .002 or .003 inch smaller than a loaded round neck diameter. Depending on how much spring back the necks to, the bushing .003 inch smaller one may be best.

[/ QUOTE ]

thanks bart

col48 · #6 05-04-2006, 10:31 AM

[ QUOTE ]
If it were me, with Norma brass and a minimum spec chamber,I dont think I'd bother.Do you know the actual neck dia. of the chamber? [/quot
dose this mean anything to you.

TPI in 20 Inches
Body TPI 0.115
Neck TPI 0.034
Throat TPI 0.5237
Pilot Size 0.27
Caliber 270
Bore Size 0.027
Groove Size 0.277
Basic Brass 270 WSM
Resize N.D. 0.296
Margin .001/.003
Tolerances MAT'L.
Unless Otherwise Specified PACIFIC TOOL DWG. BY Dave Kiff
Fractional ± .001 598 Avenue C Checked MK
Decimal + 0.0004 White City, OR 97503 Approved
Angular ± 1/4 (541)826-5808 Sheet

thanks
colin

Ballistic64 · #7 05-04-2006, 01:00 PM

col48, take a measurement of one of your loaded rounds just for curiousity.I talked to Dave,and while he didnt have the exact neck dia. spec Nesika uses,he was guessing .312-.315
Nesika usually makes thier guns to a match chamber but unless the customer specifies a tight neck,they have to chamber looser for what ever the customer shoots.To improve accuracy on thier guns Neskia will use a min. saami chamber spec with a tight throat.My guess that without turning your neck clearance is already .004-.005 and being as Norma is pretty uniform brass,thats why I said I wouldnt mess with it.Just for curiousity sake can you post the loaded neck dia.?