Necking down .308 to .260 problem

#1
I'm having issues necking down .308 brass to .260 in that it's really tough to close the bolt when I've put a piece of brass in the chamber.

Rifle: Remington 700, Remage barrel headspaced with PTG gauges
Reloading setup: Redding FL sizing die, Hornady Lock 'n Load Press
Brass: Lake City and Federal Match once fired brass
I've tried both the spray lube and the waxy stuff in the shoe polish-like can

The Hornady OAL gauge dummy brass chambers with no issue

I've run the die all the way up and down the die bushing but for whatever reason, I really have to muscle the bolt closed. I haven't charged a round yet as I don't want to be fighting the bolt on a live round.

Thoughts? Thanks for any advice you have.
 

BearNaked

Beer Saved The World
#8
I use the same brass and you have to use a small base die then turn the necks. ive found that LC military brass necks range from about .013-.018" thick.

if you have doubts what is causing this, take a black permanent marker and color the top half of a case. then run it through the action and it will show you were its hitting with scratch marks. I would bet $100 its the case necks being too thick.
 
#9
Methinks that spife, itwillis, and BearNaked are on the right track.

When I first "made" .260 cases from .308 cases, I was pleasantly surprised how easy it was... one pass through the .260 resizing die, and TAHDAH!!! .260 cases were made. No longer would I have to buy expensive .260 cases, I was going to simply buy .308 cases and resize them and show 'em how it's done. It was glorious. It was beautiful. It was amazing. It was problematic as soon as I tried to chamber one in my rifle. Shit.

After a bit of measuring, I determined that sho' nuff, the OD of the neck was too thick, and I was left with a choice... either I could spend the cash on a neck turning setup (realizing that the cost of such would pay for a lot of .260 cases), or I could give up on my dream of being able to utilize .308 Win brass in my .260-chambered rifle. What to do, what to do...

I really like my 21st Century neck turning setup.
 
#10
I've come to the same conclusion... I think I'm going to get the neck turner. I have a few thousand 308 cases that I can start with (still shoot 308, so I'll keep a half 308, and resize the others).

After I shot the necked down cases the first time, they seem to seat better now after fire-forming. Still a little tight, but not nearly as bad.
 
#11
Well, I think that this has been figured out but here is my 2 cents. I used to convert 308 brass and yes, in fact, your necks are too thick, that solved it for me. But I will say that I have had better luck converting 243 brass ( still need to neck turn it for better concentricity), and now I just said screw it and I buy 260 starline brass. not as good as the Lapua but I don't cry as loud when I lose a piece in a match.
 
#13
You can buy .243 cases and size up to 6.5. Case length is the same for .243, .260, and 7mm-08. Before neck turning, you need to run an expander mandrel through the case neck, and use a turning mandrel in the neck turning cutter. Otherwise, the necks will be too tight to turn on the neck turning mandrel. Once it's all set up (and it is a royal pain!), it's quick and easy; and once a case is neck turned, it won't ever need it again, most likely.