Thread: 7mm rem mag neck sizing

What’s everyone’s go to for neck sizing? Using rcbs fl.

Federal brass ?

Hornady. About 5 firings, federal lasting a little longer. About to start using adg and not going to let this happen to it.

Best to resize off shouldet, not the belt.

Yup, keep winding your die out until the case wont quite chamber and then wind the die back in about 1/4 turn. And check every case every time with the fine wire scratchy technique that will let you know about incipient case head separation about 1 load before its too late.

Fortunately it wasn’t too late this time only noticed this when it came back from annealing.Been reading people seem to do 3 to 4 neck sizing then bump the shoulder.

Originally Posted by DylRuss

Fortunately it wasn’t too late this time only noticed this when it came back from annealing.Been reading people seem to do 3 to 4 neck sizing then bump the shoulder.

Only need to bump the shoulder if it wont chamber from the neck sizing. I cant remember how many times I've neck sized mine, cant even recall the last time I bumped the shoulder. And they still seem to chamber nicely.

Hornadies Neck sizing die should answer your call.

I've had the same issue, ended up NSing till the brass would not close in the chamber, only then did I use the FL die and I only pushed the shoulders back by 4 thou and locked the die at that setting. After that I could FL size without issues.

I have been using the Redding FL bushing die - I just set the thing up without the decapping stem and set to just kiss the shoulder at the point you feel the case when closing the bolt and it seems to work for me. If you have a case that's a bit reluctant to chamber, take the bushing out and wind the die down a smidge more and that's the new set point (if you're gentle the die without the bushing is a nifty shoulder bump die).

Currently using a Lee collect die for neck sizing. However, I'm planning to try a Wilson full-length die with neck sizing bush.

Cool, all good info there guys. Thanks

You can get a collet sizer for the head to extend the brass life out a fair bit more

I used a RCBS neck sizer to good effect on rem mag in the past. Full length sizing is more consistent but yes if you oversize you will get that nasty separation happening.

I used Winchester and the Federal brass. Winchester it was the necks that gave trouble with splitting. Federal it was the primer pockets that gave up before I had any other issues.

Lee collet sizer is good but I found that as the brass got older and harder after a couple of firings it didn't size enough. Annealing would have helped there.

Personally I hate the admin that comes with full length sizing (applying lube, trimming, cleaning brass etc), neck sizing works well with belted cases.