I began to reload for my .300 Weatherby and been reading about headspacing on the shoulder rather than the belt. I use RCBS dies and would like ot know how to set up the die to achieve this rather than full lenght resizing.I reload for about 10 unbelted calibers and always full lenght resized. Thanks for the replies

NO problem. Set your sizer to touch the shell holder and back it out a quarter turn. Size a fired case and chamber it in your rifle. It likely won't go, shouldn't anyway. Turn the die down 1/16th turn and try again. Keep it up until the case chambers with just a touch of resistance. Lock the sizer ring there and leave it there or plan to do this all over again. (Do it this way with all bottle neck cartridge, belted, rimmed or rimless.)

You can buy tools to do it with but using your own chamber as a sizing gage is fine for most users.

I mark the neck shoulder with a dark marker looking at the smug the die makes on the mark I set the die to allow me to just touch the shoulder. Or if that leaves it a little tight after a couple loading turn the die in a quarter turn or so.

Ram a quarter turn on a die equals about 16 thousants of an inch change in headspace, that's far too much. It will surely produce a sloppy fitted case, excess headspace, and lead to the case stretching we want to avoid. The 1/16 turn is about 4 thousants and that's plenty of change for each adjustment!

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Ram a quarter turn on a die equals about 16 thousants of an inch change in headspace

You are right. I know how much I turn it without thinking. I should have given my answer more thought. Thanks for the catch

I have a .338 win mag. and I touched the shellholder with the die and backed it out 1.5 turns, sized the case and it chambered. It was a little snug but it still chambered with very little effort. Am I doing something wrong? I read that it shouldn't chamber at all. Thanks for the replies...PaLuke

What's happening is you are working with 1x fired brass and it hasn't grown to the full length of the chamber yet. Lets say your chamber has room for .015 growth but on the first firing your brass grew .010. Then by fl sizing it grew another .005 inch even though the die was way out. NOW, on the next firing your brass will grow to chamber length and if the die ins't right you won't be able to take another .005" growth at resizing. The 2nd resize is where you have to get the die right. I think I would bet you a 24 pack if you don't reset the die closer to the shellholder the next resize won't chanmber at all.....this is the moment of truth.

Thanks for the reply. That answers my question. I reloaded for about 20 years and always full lenght resized but just started with belted cases. The 338 win mag and .300 weatherby to be exact. When it warms up here I'll shoot some and then set the die. Right or wrong I owe you one. Thanks , PaLuke

You want to get all your bottleneck cases going on this idea...not just the belted mags. You can see a slight increase in accuracy with a better chamber fit. If you like reloading put a hornady headspace bushing kit on your "want list". They are about $35 and a very worthy tool for setting up dies and seeing what's happening in the gun.

The best way to achieve proper headspace is with some form of a headspace gauge. This takes all the guess work (ie 1/4 here, 1/16 turn there, slight resistance when closing the bolt) out and gives you a definitive measurement to the thousandth of an inch. All of my bottle neck cartridges are sized to give 0.0015"-0.002" headspace. In addition to improved accuracy, you are not over working the brass (it'll last longer) and the cases are less prone to stretching (you wont have to trim as often).

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Originally posted by Juggernaut76:
The best way to achieve proper headspace is with some form of a headspace gauge. This takes all the guess work (ie 1/4 here, 1/16 turn there, slight resistance when closing the bolt) out and gives you a definitive measurement to the thousandth of an inch. All of my bottle neck cartridges are sized to give 0.0015"-0.002" headspace. In addition to improved accuracy, you are not over working the brass (it'll last longer) and the cases are less prone to stretching (you wont have to trim as often).

+1

Absolutely the only way to go! If you are truely serious about headspacing on the shoulder, quantify what your sizing operation does.

- mike