Gentlemen,
I am currently using an RCBS Rock Chucker, and RCBS FL sizing dies. I know that somewhere I have read about how to adjust them to neck size, but I have forgotten where I read that. Is it screwing the die down until there is just enough space for a dime between the die and the raised shell holder, or is it different than that? I just need to size my cases less, not actually neck size, but I would like to know. Thanks.
Regards,
Graham

All you should have to do is screw the die down into the press in incremental steps. Put a case in the shellholder, run the ram to the top of its stroke, and screw the sizer die down until you feel it stop against the top of the case. Then drop the ram, go in another couple of turns with the die, and tighten the lock ring hand tight. Then run the case into the die, and back out. Examine the neck, and repeat, turning the die down roughly a turn at a time, and inspect the neck of the case each time you adjust the die and re-size. Go slow, and size the same case again and again. You will see a "mark" on the neck and a diameter difference; that will tell you how far down the sizing has progressed. Once you have sized the mouth enough to hold a bullet securely, I feel you have gone as far as you need to. (Some gun writers say one caliber length is all that is necessary...) When you are satisfied with the amount of neck that has been re-sized, secure the lock ring on the die with the set screw, and you will be able to return to that point each time you size.

M70classic

I use a little different method than Doubless.
I run the ram to the top of its stroke. Now I screw the die down to touch the shell holder. To full size resize you would drop the ram and screw the die down 1/8 more. But I do the reverse I back the dies off just a little over an 1/8 of a turn and lock it in place.

I make one dummy round and check it to see how it chambers. If it's good I put the dummy in the die box and the next time you load just put it in the shell holder move the ram to the top of the stroke and screw the die down on it until it stops.

If you size them a hair to little they are going to be hard to chamber. If you really want to just neck size instead of partial size I go to Ebay and find myself a neck die. Depending on the gun and what it seems to like I do both.

I put a nickle on the shell holder. Screw the F/L down tight. Works for everything from 280AI to 17AH. Smoke your case and set it from there. I keep the same nickle beside my press.

I set the die up as for FL resizing and tighten the locking ring. Then remove the die and place a 7/8 machine shim (looks like a flat washer with 7/8 hole, available at larger hardware stores) underneath and reinstall. (shim is about 0.075") Shim out - FL resize, shim in - NS, never have to change the setting.

There really is no such thing as "neck sizing" with a full length die....all you are doing is not bumping the should back a bit from the chamber dimensions. You can call it what you want.....I'll nick name it 98% full length sizing.

quote:

Originally posted by kraky:
There really is no such thing as "neck sizing" with a full length die....all you are doing is not bumping the should back a bit from the chamber dimensions. You can call it what you want.....I'll nick name it 98% full length sizing.

You’re absolutely right it's a partial resize. I've found some of my rifles perform the best with this type of sizing. It also seems to be beneficial to brass life over FL resizing.

One last thing...and others will certainly debate me on this but I've found that if it takes extra tension to close the bolt on my rifles it often causes worse accuracy...usually with horzontal stringing. Others have posted they think this helps accuracy but I sure haven't found it to be so.
Don't know if any of you have seen the "magnum collet die" that squeezes belted cases back to original factory virgin dimensions...but it seems to be finding some real popularity with some of the long range shooters.

quote:

Originally posted by kraky:
There really is no such thing as "neck sizing" with a full length die....all you are doing is not bumping the should back a bit from the chamber dimensions. You can call it what you want.....I'll nick name it 98% full length sizing.

Right again kraky!! You cannot "Neck Size" with a "Full Length Die".

IME

You can neck size only with a full length die. Raise the ram and adjust the die down until it contacts the shell holder. Then back the die back out 3/4 turn or more. At about that point is where the die first begins to resize the case body, in most cases. If your chamber is oversize, it is possible that some case resizing may happen before that point, but it will be minimal.

The neck will be resized about 3/4ths of the way down. You can gauge when the case body
begins to be resized by chambering the case as you adjust the die. When the case body first begins to be resized the shoulder will be pushed forward and a crush fit will result. This crush fit will persist until the die is adjusted enough to push the shoulder back. That happens about 1/8 to 1/4 turn past where the die hits the shell holder, in most cases and with RCBS dies.

Not that I do it that way anymore. I use a Lee Collet Neck Sizer

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=329661

and a Redding Body Die to push the shoulder back when needed

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=418978

If you have a Stoney Point Head and Shoulders Gauge it is easy to follow this progress and push the shoulder back .001 to .002" for Partial Full Length Resizing.

Thanks ya'll for the very useful information!
Thanks for the correction, Kraky. I only really wanted to partially resize, not neck size. I am first of all a hunter, not a benchrester, so ease of chambering is of very high priority. Thanks again for the help.
Regards,
Graham