Sizing belted magnums any tips???

[yotebuster]

I just recently purchased a 7mm Rem Mag and have heard many different ways to resize the cases and was wanting to know how your best luck.

 

[Hipshot]

Up to now, I've resized my 7mm Weatherby Mag using a FL die but set to only move the shoulder of a fired case back by .001. I have, in the old days,BS=before smart) set the die so that the shellholder was up against the bottom of the die. What I found out was that the brass grew like Pinoccio's nose.

My experience with 6BR leads me to want to change the sizing die to a Redding FL bushing die and throw away the expander ball. I'd still size just enough to bump the shoulder back .001.

I'm also interested in other opinions. After all, I'm still BS.

 

[tripcrow]

I’ve always neck sized belted mags under the belief that it’s best to take the belt out of the equation as much as possible. Before taking any necked cartridge hunting, I’d run them through the action to be sure they all chambered easy. If they go in hard check the headspace with a gauge like the Stoney Point setup. If that’s Ok you may need to bring the body back in. And that’s hard to do sometimes even when you cam over on a FL sizer.
Never tried this, but have read from guys that it works pretty good.
http://www.larrywillis.com/
His site has some good tips on loading belted mags.

 

[Preacher]

That Larry Willis die is almost a requirement if your loading a lot of belted cases very many times.......

 

[Lane]

Accept the fact that the interior dimensions of a die is dictated by the manufacture. Accept the fact you will be working with a rimless belted case and head space is controlled by the belt. Understand that both the die manufacture and the rifles chamber are designed with this in mind. Full-length re-size if you do not have the means to measure precise adjustments with your die and how your cases are being sized to correctly fit your particular rifle chamber. In my opinion if you have the means to measure any run-out in your particular rifle chamber then you have the potential to do something other then full-length re-size your cases. Potential! Full-length re-sizing is a great way to go sometimes! Tip #1 know what your case measures at the critical control points on the case before you fire that case in your particular rifle chamber. Wish you all the best!

 

[Hipshot]

Interesting points, Lane. Is there any reason that a belted bottleneck case cannot headspace off the shoulder rather than the belt?

 

[Cheaha]

Forget about the belt and size like any other case. Bumping the shoulder back a thousandths will work just fine...

 

[Twud]

I've probably reloaded 500 rounds between my 257 and 300 Wbys and have never full length sized. Neck size only. I've never had a feeding or extraction problem and I believe it contributes to improbed accuracy. I don't shoot super hot loads and have only ever used Norma brass. JMHO

 

[Lane]

Interesting points, Lane. Is there any reason that a belted bottleneck case cannot headspace off the shoulder rather than the belt?

Yes! one reason would be a belted case that is shorter the then minimum SAAMI standard dimensioning tolerances. This is the reason you can not just blow off the factor behind a specific case design. A belted case is designed to have headspace controlled by the belt not the base to datum length. You can ruin a belted case the first time they're fired. How much did that specific belted case have to stretch to headspace on the case shoulder? What is the base to datum length of new brass in comparing to once-fired brass from your particular rifle chamber? How much will the case have to stretch to headspace on the shoulder? The dimensioning & tolerances of the die, brass case, and particular rifle chamber are all based on SAAMI specifications that work off the fact that with a belted case headspace is controlled by the case belt. The problem is case stretch how much and how many times! Wish you all the best Lane

 

[JamesinAsheville]

I have always neck sized and bumped the shoulder back .001 or so to get the right feel of the bolt handle closing and never had any trouble with brass stretching or any thing else. My 7mag really started showing good groups when I started n/s and I've never changed. That's my experience.