[TexasShooter59]

Does anyone out there neck size their belted magnums using a full length sizing die? I would like to hear how well it works for you, what cartridge, and any pros/cons you know about or have experienced.

Thanks!

[ForneyRider]

Been playing around with my Rem. 7mm Mag brass and sizing with FL and neck (collet) dies that came with Lee Deluxe rifle set on my Lee Breech Lock.

The cases keep getting stuck and I end up pulling the rim apart. Loosening the decapper pin and then tapping it with punch and hammer pops out the case. But then I have to cut the case to get the decapper pin out. Been making a real mess of things.

When I did this in last batch, the neck tension wasn't enough to secure my bullets. I tried several bullets, several from different sizes, and they all were loose after using the neck-sizing die. Turns out I wasn't applying enough pressure and/or the die wasn't adjusted correctly. I ended up just touching them up with the FL die, and the neck tension was better.

These brass are primed and I was too stingy to pop out the primer to run them through the neck sizer again. With the FL die, you can just push up the pin some. After reading some, this is probably a bad idea too, because I don't think the Lee dies don't have a place for the air to escape like the RCBS dies do.

I do trim to length all the rifle cases I reload. I am hoping to trim more off the Winchester brass, because of the ugly crimp they put on them. It has rectangular divits(sp?).

This has been the problem with Winchester brass from factory ammo. The bulk new brass I bought(Remington, Nosler(Federal), Winchester) I haven't had these issues.

[Bad Flynch]

Well, years ago when I loaded for 7mm RM, I tried this. However, one really never gets a true "neck size" by using a F.L. die and backing it off. What one gets is a partial sizing and that may be good or bad.

By partial sizing, one squeezes the sides of the case in, but the shoulder remains, to a degree, untouched. That allows the shoulder-to-head dimension to grow in some instances. Occasionally, the shoulder dimension gets long enough to cause difficult chambering.

Belted magnum cases headspace on the belt, not the hsoulder; belted cases with a shoulder have a "sort-of" dual headspace situation: the belt determines the headspace, but the shoulder determines the chambering. Sometimes that dimensional relationship gets out of whack when partial sizing.

Your best bet is to buy a F.L. sizing die and a device that will measure the shoulder-to-head dimension of cases fired in your rifle. Then set the F.L. die so that it moves the shoulder back about 0.002" or so, when you use it.

However, you need to use a regular "Neck-size-only" die for neck sizing in most cases, using the F.L. sizer to set the shoulder back after the cases have been fired a number of times and get tight in the chamber.

I recomment that you buy the Redding set that has the neck sizing bushings; they are available in F.L. and Neck-Only styles and if you do your measuring right, you can throw away the inside expander button and save your brass. The 7mm RM has a tendency to work-harden the necks and the necks get very springly. The sizing bushing, used without an inside expander can help get around this and keeps your ammo thusly loaded much straighter, too.

[steve4102]

However, one really never gets a true "neck size" by using a F.L. die and backing it off. What one gets is a partial sizing and that may be good or bad.

By partial sizing, one squeezes the sides of the case in, but the shoulder remains, to a degree, untouched. That allows the shoulder-to-head dimension to grow in some instances. Occasionally, the shoulder dimension gets long enough to cause difficult chambering.


Exactly, Well Said!

[TexasShooter59]

Thanks for the inputs - I ordered a neck sizing die to go with the full length die set.