If you have some factory loaded rounds would you please measure the neck diameter.



What is considered the proper neck diameter for the 6.5/308 AKA .260 Remington?



Thank you in advance.



D

Don't own a .260, but my Sierra manuel shows 0.297 on the .260 diagram.  Here's a link to decent spec sheet.

http://www.6mmbr.com/cartridgediagrams.html#260REM

Thank you, great link  

0.0135" neck wall thickness and a 0.264" diameter bullet yields an overall neck diameter of 0.291".  I'll go measure some of my reloads and get back to you later.

Thank you Mike,  I would be loading my own...

If you're ordering bushing dies, then don't forgot to account for some neck tension.

If you're ordering a reamer, a .297 neck would work very well.

The man is clairvoiant...
still at the reamer stage with this one.  And I am familiar with bushing dies.. wouldn't use any other type.

Ah.

My .260 reamer has a .294 neck, and I can shoot factory ammo in it with no problem.
The plan is to use necked down Lapua .308 brass, for which I've been told I'll need to turn the necks.
I haven't done this yet, but it's coming... soon as I get some dies.

Zia, I have the Redding .308 bushing dies and plan to use them with my 6.5/284 Win's bushings...  That rifle has a .295 neck as it was made before Norma nad Lapua made brass for same.



I also think that either necking up .243 Lapua or down with the .308 should be nice.  I am going to test some brass later with said theory.  My local gunsmith recomends going up not down...

I think most agree with your smith.  My smith says to go down and turn necks for custom fit.  I cheated, I broke down and ordered a bunch of black hills .260 from GAP.  No muss, no fuss and come with a lapua bullet.  

I'm hearing the rem .260 brass has gotten a bit better in their qality.

I made some measurements on my gear for you.

The Hendricksen (sp?) chamber reamer used by McBros on my barrel supposedly has a 0.298" neck diameter according to the chambering reamer drawing.

Fired brass, after several firings (but not a lot of firings) measures 0.296" diameter (0.002" spring back?).

Loaded rounds using the 107 gr SMK, measured 0.291" to 0.292" diameter for Remington brass.  

The batch of Remington brass I have is surprisingly good quality in terms of case weight uniformity and neck wall thickness uniformity.  Watch out, though.  I found a HUGE, multi-grain weight brass shaving (curled brass trimming) inside one case.  I only found this because I took the time to do some weighing of the cases.  Normally, the case would have been loaded and fired with this HUGE shaving inside.  In another case, I found the flash hole punching pin from their brass forming die which was broken off and stuck in the flash hole of one case.  After inspecting these defects out of the brass, it was great.

I hope this helps in some way.

I don't have one, but someone told me the .260 is basically a 6.5mm-08, between the .243 (6mm-08) and the 7mm-08.  That being the case(no pun intended), I would submit that the assembled neck diameter should be bullet diameter + 2 x 0.015.