case neck resizing only using RCBS full length resizing dies

[eaglesnester]

I understand it is possible to only size the neck in once fired rifle cases using a full length reloading die. Doing this will preserve the expanded case size to only fit your chamber on your rifle and will reduce case hardening from reworking to factory specs. I know that you can order neck sizing dies only but I would like to use my full length RCBS resizing die to accomplish this procedure if it is possible. I am currently assembling a RCBS reloading bench for 308 Norma Mag. Anybody know how to do this, or am I considering an unsafe procedure?
Cheers: Eaglesnester

 

[KDM]

I would think to use a full-length die as a neck sizer only, you'd run the brass up only past the expander ball, then return. The expander ball slightly opens the mouth to facilitate bullet starting. Mind you, I've only performed full-length resizing...haven't tried neck sizing.

If my info isn't correct, at least it'll bump the thread.

 

[BigJakeJ1s]

I've never tried it, but as I understand it, set the FL die a little higher such that it just misses the shoulder, but gets all/most of the neck. You have to get the neck or the expander ball will not work. The neck is larger than it needs to be after shooting, gotta squeeze it down then expand a little back to proper size.

Andy

 

[TATER]

Here’s a trick, Simply place a dime on the shell holder then you can
go about your normal set (screw the die in until it contacts the dime)
HTH
Tater

 

[wncchester]

The dime trick may or may not work, depending on your chamber and the FL die you are using.

IF any part of a bottle-neck case other than the neck is squeezed by the FL die you are not "neck sizing" only, you are "partially FL sizing." That results in moving the shoulder forward a bit and will eventually prevent chambering of the loaded round. If you want to neck size, get the right die.

Fact is, for factory rifles, neck sizing rarely makes any difference and sometimes it makes accurcy worse.

 

[snuffy]

PFLS, partial full length sizing

That's what you are referring to. As said above, you back the FL die out, so as NOT to touch the shell holder. BUT, you will size part of the body of the case, UNLESS you have the die backed WAY out to only size about half way down the neck.

 

[steve4102]

You cannot "Truly" neck size with a FL die. The FL die will still come in contact with the case body. If you want to Neck Size only purchase a Neck Die. The best I have found is the Lee Collet Die.

 

[Uncle Don]

I wouldn't think it would be a reliable thing to do. In order to size the neck, the case only goes partially in. When that happens, the body of the die sizes a small portion of the bottom of the case but not all. Since it is squeezed near the bottom and still having room to move upward at the top, I would think you would extend the length of the case causing it to have trouble closing in the chamber.

If I want to neck size, I simply use a neck sizing die as that doesn't attempt to size the bottom of the case at the same time. Probably not an overly clear explanation, but is the best I can do on short notice.

 

[arkie2]

Fact is, for factory rifles, neck sizing rarely makes any difference and sometimes it makes accurcy worse.

Hmm. That's the first time I've seen anyone say it would possibly make accuracy worse. Still, the advantage of neck resizing only and avoiding the lube makes it worthwhile for me.

 

[MADISON]

Neck Sizing with Full Length dies

Special NECK SIZING DIES
I E-Mailed RCBS on December 12, 2004 and received the following response on December 15, 2004.

From an old #8 Speer Reloading Manual. You and other equipment manufacturers sell special NECK SIZING dies. Does this still apply to your equipment?

Neck Sizing is the term applied to the process of sizing only the neck of a case, with a special die which doesn’t touch the shoulder or body of the case. Neck sizing does eliminate excessive working of the case shoulder and body but, also, may size the neck off-center and leave the body of the case too large to chamber. A better way to reduce excessive working of the case body and shoulder metal is to use a full length sizing die but, use it so it only sizes partially. To do this, the full length sizing die is backed out of the tool so that the shoulder is not touched by the die. This preserves the important head and shoulder dimension and still sizes the neck normally. The body of the case centers the neck in the die and is sized enough to make chambering fairly easy in a bolt action.
Back the die off at least 1/16th of an inch [About one complete turn.]
Many shooters adjust their dies so that only half of the neck is sized. This leaves enough tension to hold the bullet securely for target or varment shooting

The RCBS “Ask the Expert Forum’s response was:
Yes, the necksizers only size the neck of the cases. And yes, there can be run-out after necksizing as there is nothing to support the base of the case - it just sizes the neck. AS FOR PARTIAL SIZING -- Many of our customers choose to do this - but, it is trial and error and sometimes the chamber v.s. die fit does not allow the reloader to partial size - they will not chamber afterwards.

 

[Trapper L]

The idea behind neck sizing only is to keep the fireformed datum line established by the chamber dimensions. You can easily do this by backing the die up 1 1/2 turns or use a 7/8" or 1" washer under the die. The datum line is maintained and the neck is sized. The sizing of the body is irrelevant and if it is an issue, a neck sizier only die won't work either. Some chambers are not perfectly centered to the bore axis and this can create this issue. If you have a chamber that is off centered and want to neck size only, you will have to index the brass to the chamber.

 

[steve4102]

The idea behind neck sizing only is to keep the fireformed datum line established by the chamber dimensions. You can easily do this by backing the die up 1 1/2 turns or use a 7/8" or 1" washer under the die. The datum line is maintained and the neck is sized.

The problem with this set up is that the FL die still comes into contact with the case body. In doing so the body is reduced in size and the brass has to go somewhere. Usually up and towards towards neck. This can and does push the shoulder forward. The original fireformed datum line is now lost. In many cases this can push the shoulder so far forward that the brass will not chamber.
If you want to keep the fireformed datum line in tact you need to use a Neck Die or set up your FL die to Partial FL size. Setting up the FL die is a bit more involved than just backing the die out 1 1/2 turns. You need to set it up so the die comes in contact with the case shoulder exactly where you want it.