I don't know if my brother has asked this before but I need to know how to headspace off the shoulder with a belted mag. I have been told that this will increase case life and accuracy. I load for a 7mm Rem Mag and my brother loads for a .300 Win Mag.

You might want to discuss this with John Ricks, he has a post on this same board dealing with belted magnum headspacing. Looks like he's got the situation well in hand!

Me, I just mess with the loading die until the resized case is a snug fit in the chamber and let it go at that. Works fine for my 7mm Rem mag. Not real scientific, but I think I'm just sizing the neck, and nudging the shoulder a mite. Getting great groups and good velocity, so I'm not going to take a closer look! Regards, Guy

You can do this a couple of ways. first you can fire a round (fireform), set the die to size just the neck, holding short of the neck/shoulder junction and check the fit with the firing pin and bolt nose ejector removed so as not to get a false feel when the bolt closes, Ideally, you want to bolt to close with contact on the round. Adjust the dies until the bolt just closes with contact. Another way is to neck the brass up one caliber and then bring it back down to size, again holding shy of the neck/shoulder junction. If done properly, this will give the brass a stopping point based on the position of the newly formed neck/shoulder which is what you eventually want.

The idea is to have the brass held in position at the base of the case and at the shoulder, bypassing the belt. The proceedure is nothing more than fireforming and then selective neck sizing. Done properly, not only will your brass last a bit longer, your groups should tighten, all else being equal of course.

Note: you may have to have the belt position changed in your die in order to avoid contact during sizing if full length sizing is your thing.

I do hope this makes sense...

Malm