Neck size or full length size 300 win mag?

[mattri]

For those who are loading the 300 win mag do you full length or neck size and why? Thanks, Matt.

 

[4xforfun]

My answer is ....both. The problem with FL sizing for most people is this....they screw the die in all the way to the shell holder and size the case. Now...if all is right with the world and Venus lines up with Jupiter.......well you get my point. Most people don't know how to accuratly adjust for proper headspace. Now...since you shoot a belted mag (the case headspaces off of the belt, not the sholder) you will never have this problem...you just may well be over working your brass which can lead to another problem....case head seperation......VERY DANGERIOUS!!!! Those who shoot non-belted casses can have trouble right out of the shoot.

Even though I have all of the tools and verry capible of adjusting for the proper headspace....I neck anyway, even for competition....easier....less mess.....no overworking of brass. I just run all of my neck sized brass through the gun before I load to make sure they all fit. I also remove the firing pin so I can better feel the fit of the case in the chamber.

As far as full length sizing....if you are short of measuring tools....remove the firing pin from your bolt, set the die a couple of turns out from the shell holder, and start sizing brass and trying them in you chamber. Keep turning the die down untill the bare bolt will almost fall into the locked position un-aided. Remember to wipe the sizing lube off before you run the case into the chamber.

Hope this helps

 

[louielouie]

My Mod 70 has a 'generous' chamber and throat so neck sizing is the only way to save brass for a few loadings - had a case head fall off when I looked at the brass after FL sizing it 3X. If I ever re-barrel this thing (my shoulder doesn't appreciate 200 gr Sierra BT's anymore) I'll ask for a tighter chamber.

 

[buckbrush]

My Mod 70 has a 'generous' chamber and throat so neck sizing is the only way to save brass for a few loadings - had a case head fall off when I looked at the brass after FL sizing it 3X. If I ever re-barrel this thing (my shoulder doesn't appreciate 200 gr Sierra BT's anymore) I'll ask for a tighter chamber.

The converse of this is something I experienced when my chamber was so tight that two different RCBS full length sizer dies could not size the 2x fired brass enough to fit back in the chamber without major effor to close the bolt. Once I got a Redding full length sizer, they would chamber. Brass life is very good this way though since it is hardly being worked. I've had over 8 firings on WW brass with fairly hot loads out of this chamber.

 

[4xforfun]

My Mod 70 has a 'generous' chamber and throat so neck sizing is the only way to save brass for a few loadings - had a case head fall off when I looked at the brass after FL sizing it 3X. If I ever re-barrel this thing (my shoulder doesn't appreciate 200 gr Sierra BT's anymore) I'll ask for a tighter chamber.

The converse of this is something I experienced when my chamber was so tight that two different RCBS full length sizer dies could not size the 2x fired brass enough to fit back in the chamber without major effor to close the bolt. Once I got a Redding full length sizer, they would chamber. Brass life is very good this way though since it is hardly being worked. I've had over 8 firings on WW brass with fairly hot loads out of this chamber.

I think you gave the answer to your problem...."fairly hot loads". It does not matter how tight the chamber is......if the new brass fits without any effort when new, it should re chamber the same way after you fire it...unless it is fired way too hot. The brass takes the shape of the chamber, big or small (I am NOT talking about headspace issues)

Another problem I have seen with the symtoms you stated was...when you FL size your brass the first thing that happens is that the brass gets longer.......you squeaze in the sides and it grows longer. If your chamber is a touch short, or your die is a little long, you won't get to the "sholder bump" part of the process, even with the die screwed all the way down to the shell holder.......your brass will be hard to chamber because the sizing prcess has made it longer. Just as an experement....turn .020 thou off of the old RCBS die and try it again. Any machine shop should be able to chuck it up in and shorten it.

I do agree that if you have a big chamber and a small die that you will be over working your brass when you FL size. This is where the "neck size only untill the brass starts to chamber tight....then FL one time to get them back down and resume the neck sizing" regiment fits in.

Hope this helps....or even makes sence!!!????

 

[30378]

I neck size mine. RL-25 and 165 Accubonds.

 

[mattri]

Thanks for the replies.

30378, what is your barrel length/twist?

How many loads do you get out of your brass?

Thanks, Matt.

 

[bheadboy]

I shoot a 26" hart 9"twist on a 700 trued action. I neck size with a slight touch of the shoulder, using lube on the shoulder to see when it touches to set the dies.

Loadis h4831 with 180s at well over 3000fps shoots .4"
Win brass shorted
Bob

 

[TonyD 300 WM]

Im am about 2 months in and about 50 rounds fired with my 2 300 WM rifles. I am new to this site and look foreword to gaining as much as I can about the science of reloading. I have 5 manuals and use the powder sites for most of the loads. I have loaded all my pistol (9mm, 10mm, 40, 45 ACP) and rilfes (223/5.56, 308, 30-06, 300 WM) most are AR 15/AR 10, an WIN 70 30-06 and Mossberg Patriot 300 WM rifle. Reading thru this I want to start a target long range load for my Remington Long Range 300 WM. (the old USMC 700 A3). I mixed the brass from both the patriot and Rem, my fault, but I have started to separate what is firerd thru which rifle. I also have 50 not fired brass to use for the Remington. The rest I will used for the developing of a hunt load. I think I bought a box from Nosler 150 thru 180 to see which load is best for hunter per grain of bullet...maybe too much?

My question is I have a neck die and the FL RCBS die, I want as much life out of the brass as possible. So how can I establish head-space exactly with the FL die on the shoulder rather than the belt if I am sending the shell up thru the FL die? 4x mentioned machining the die, this seem to be the best route to take rather than FL sizing the die, right? Should I just eliminate the FL die and stick with neck sizing? I have next sized the last 25 rounds fired thru the mossberg and they chamber great. I haven't yet done much with the Remington, its chamber is much tighter. I bought the bullet Comparator and head-space guards for the micrometer form Hornady.

Look foreword to the feedback. Any other resources you have for me would be greatly appreciated.

Thanks
Tony

 

[js223]

My question is I have a neck die and the FL RCBS die, I want as much life out of the brass as possible. So how can I establish head-space exactly with the FL die on the shoulder rather than the belt if I am sending the shell up thru the FL die?

I bought the bullet Comparator and head-space guards for the micrometer form Hornady.

With the Hornady headspace gauge, check the position of the shoulder on the brass that was fired in the rifle that you wish to reload that brass for. Write that dimension down. Then set the FL die higher in the press than normal for starters. Try sizing the case and then check where the shoulder is with the gauge. You can then adjust the die down in the press (try,measure,repeat if needed) until you find that the shoulder is bumped whatever distance you wish it to be.

 

[Zero333]

I use the Hornady Headspace comparator and it's important to deprime the fired case before getting the initial measurement.
I put a fired case in the shell holder on a flat surface and punch the primer out with a hammer and a long thin nail or other device.
I bump the shoulders 0.001" and that is as far as my sizing die can do because I set the headspace of my target/LR 300winmag at 0.002".

 

[slm9s]

Lee collet die to neck size until I feel resistance on chambering, then FL size.

 

['Freak]

Any case that “headspaces” on its rim or its belt needs to have the size die adjusted such that shoulder setback leaves only a thousandth or two of case stretching space left between the case’s shoulder and the shoulder of the chamber. Its length from case head to shoulder datum is measured the same using the same tools, and a FL size die is adjusted the same as if it were any other bottleneck case, as if the belt or rim doesn’t exist.

I’ll never figger why folk ever suggest you back out a size die “one or two turns” when with a thread pitch of 1:14, that’s raising the die .071” to .143”, way the heck a lot more than necessary to make reasonably sure that the die never gets anywhere near much less touches the case shoulder. A quarter turn makes a lot more sense though it’s still likely more than enough at .018”. Half that or backed out one eighth of a turn from initial shellholder contact means ~ .009” less shoulder bump and more likely that it’ll end up within ballpark range.


'Freak

 

[hogan]

If really concerned about brass longevity and Precision bullet delivery, consider having your barrel set forward so virgin brass headspaces on the neck.

 

[DRNewcomb]

Technically, belted magnums are designed to headspace on the belt. That has a history going back several technological generations to the 1920s and the .300 H&H, which lacked any definable shoulder. Today, the belted cases are used because they are big and consumers equate them with "magnum". Can anyone think of any reason that just neck sizing with a shoulder bump would not both improve accuracy and increase brass life in a belted magnum? I can't. As long as you're only loading for one chamber.