Gents;
Please advise on an accurate way to establish the positioning of a full-lenth sizing die (RCBS) to effect only a neck size. I understand that one can not use these cases in a rifle other that the one in which it was fired the previous time.

Is it safe to assume that, once a bullet can not be pressed into the neck without a seating die, that I achieved my aim? At present, I am probably wearing out brass unnecessarily as I position the press ram/shell holder to touch the base of the die even for cases only being fired in my rifles (.223Rem; .270Win; .375H&HMag). I am aware that one can procure a Collett die for this purpose, but would be delighted if I can achieve the same by only modifying my existing settings. The US Dollar prices of these items are quite prohibitive when converted to South African Rands!

Karoo, I suppose the answer is "yes, but".

First off, the amount of neck tension is important, maybe even as important as the distance to the lands. More tension makes loads more consistent, with the exception, I dare say, of loads with bullets jammed. So I would neck size down at least as far as the heel of the bullet (flat base), or the top of the boat tail.

Second, when neck sizing with a F/L die, you will still end up getting neck cracks pretty quickly, on the average. The reason is that a neck die will size the brass down, and then back up (with the expander ball). This gets worse with thick-neck brass. So your actual benefit may not be as large as implied.

Third, neck sizing with a f/l die puts you in a situation where you are pulling the expander ball through the neck, but the case is not well supported. This is thought to invite run-out problems. Cleaning the inside of the necks with a brush, using lots of lube and polishing the expander ball to a mirror shine will help minimize this. HTH, Dutch.

Karoo,
To my knowlege you can not propperly do neck sizing only with a full resizing die. It will save you a lot of time and effort to spend the R250.00 on a neck sizing die and neck sizing all your once fired cases. This will also prolong the life of your cases.
Good Luck.

You might also forget neck sizing and just FL size in the proper manner. Your ammuntion will be more reliable and may be even more accurate.

Most of the long range target shooters FL size only. So do I.

KAROO,
I may be lazy, but I found the best way is to just buy the neck sizing dies. You'll be further ahead in the long run.

Karoo:

I simply must take issue with these replies.

"Neck Sizing", or more properly, partial resizing, is easily and effectively done with full length dies. Simply back the die out of the press enough that the die does not set back the shoulder of the case (about .04 to .05 inch or about 1 mm or a bit more if you wish). This will size about 90% of the length of the neck, depending on the design of the case. This is ample for proper bullet tension.

With the die screwed all the way against the shell holder head, you may be reducing the base-to-shoulder dimension to less than already-short factory dimensions, depending on the die design and the shellholder compatability. Blythely resizing to bump the shellholder is nearly always WRONG, even if you do wish to full length size.

There no reason that partial resizing with FL dies should create greater run-out than conventional neck dies. In fact, just the opposite is true. Only a collet or similar die will neck size more accurately than a FL die.

While it is true that most expander buttons are excessively rough and do "pull" at the neck as it is expanded, this is true whether you are FL or Neck sizing. Polish the expander and lube the insides of the necks adequately. Be sure to clean the lube thoroughly after resizing.

You obviously have a strong grasp of what you're doing as you realize that FL sizing will quickly result in case failures, typically a separation at the pressure ring near the base of the case. In addition, all that brass that is flowing out of the pressure ring area is ending up in the neck, so your cases "grow" with each firing and need trimmed frequently. This is just another down-side of full length sizing when such sizing is not necessary.

Good luck and best wishes to S.A.

My most accurate rifle is a 6mm Remington International in a 40-X. All ammo has always been loaded with partial neck sizing in a RCBS FL die!

But this case has a lot of body taper and a very long neck. I just touch the body of the case with the die firmly and neck size about 1/4" down the neck.

This system produces very reliable ammuniton. The loads are usually on the light side.