Equivalent of Neck Sizing?

[Poset]

Not to initiate a major discussion on the relative value of neckksizing - I realize there are two major camps (worthwhile / not worthwhile), but...

Normally, full length resizing sets the shoulder to SAAMI specs. If I adjust my full length die so that it bumps the shoulder back only a couple of thousandths each sizing, have I accomplished the same purpose, in terms of accuracy, as neck sizing only?

The thought comes from an article on another site:

"Ideally, if intended for a single rifle, the shoulder should only be moved a couple of thousandths and that’s it. This saves wear and tear on cases and improves accuracy. This can be accomplished by adjusting the die upwards half a turn or so and sizing a case. Chamber the resized case and you should notice that it takes some pressure to close the bolt. Simply adjust the die down in small increments until this bolt pressure is eliminated. At this point, if you turned the die in with small increments, you have just “bumped” the shoulder. Remember we are only looking for a couple of thousandths here."

Setting aside the benefit of neck sizing in reducing case wear and extending case life, is there any accuracy incresease inherent in neck sizing which would not be realized thru the process described?

I neck size all my brass until the bolt becomes hard to close, then FL resize, but by the time some cases reach that point, I usually have a few which are so tight the bolt will not close (without using a 3 lb hammer), so have to knock those apart... a lot of trouble. My alternative is to cycle every case thru the rifle after sizing / before loading... also a lot of trouble. Seems the procedure described bight be the best of both worlds...?

 

[rick smith]

What you are describing is called Partial Full Length Sizing or PFLS. It is a very good method. Far better than FL of all your cases. I do that when my cases start to get snug in the chamber from repeated neck sizing. I don't do it every time simply because I don't want to mess with case lube every time I load and you need to lube to PFLS. My accuracy is the same with neck sizing as PFLS on the rifles I have checked.
If you decide to use this method, wait until you have several tight or snug cases to use to set your die. Using a once fired case will not gain anything, it is already loose in the chamber. Don't use the same case repeatedly when setting the die. They can work harden and not give you a true setting. Remove the expander ball when starting. Once you have reached the point where the shoulder is being set back 0.001-0.002" replace the expander ball to see if this makes any difference. If it does, polish the expander ball to a mirror finish and use a dry lube in the neck and check another case.Rick.

 

[kraky]

I have a couple calibers that I do lots ofreloading for. I can tell you that if you want a really really sweet set up get yourself a lee collet die and follow it up with a redding body die. You will have fantastic runnout and there is something about the body die that really seems to minimally reset the body and shoulder very accurately.
I also like the idea that I don't have to remove lube from inside the case neck. The two dies together will probably be cheaper than a fancy competition die and I guarantee you will love the flexibility these two give you. Also....if you goof and have brass that is loaded and won't chamber well.....you can actually run the loaded rounds through the body die and take them back to your rifles chamber dimensions......I've done it lots of times.

 

[steve4102]

Here is a detailed explaination of how to set up your FL dies to PFL size. This procedure will work with once fired brass from your rifle.


1. Put the Shell Holder in the press and raise the ram.

2. Screw the Full Length(FL) Die into the press so it is about a "nickle's thickness" above the Shell Holder.

3. Lube a "Fired" case (walls and inside the neck) and squash it.

4. Remove the Lube and try closing the bolt on it in the chamber.

5. If the bolt closes with no resistance, screw the FL Die into the press about 1/8-1/4 turn and repeat steps 3 & 4.

6. As you feel the resistance begin, slow down how much you screw the FL Die into the press so you are at about 1/16 of a turn, or "Fine Tuning". At some point you will not be able to close the bolt and you are extremely close to having the FL Die in the proper position.

NOTE: The reason for this is because the FL Die has begun Resizing the Case-walls down to the Pressure Ring. As it does so, the Case-body lengthens slightly which in turn moves the Case-shoulder slightly forward. Then as the "Fine Tuning" continues the Case-shoulder makes contact with the FL Die and is moved slightly reward(or slightly shortens the Case-head to Case-shoulder dimension).

7. Stop when there is a slight bit of resistance when closing the bolt on the empty case. You now have a "slight crush fit" for the case in that specific chamber, or Zero Headspace.

8. Once you get it where you want it, take some masking tape or a black marker and put a Witness Mark where the FL Die Lock Ring is positioned to hold the FL Die in this position. Loosen the FL Die and return the Lock Ring to align with the Witness Mark and sung up the Set-Screw.

Screw the FL Die back into the press and try squashing another case. It should have the same resistance as the previous one. If not, you need to re-adjust the Lock Ring so it does. But you are extremely close to where you want it, so make very small changes at this point.

Occasionally check the fit of the cases in the chamber, say every 5th firing just to make sure nothing has slipped. Checking more often won't hurt anything and give you confidence that the Set-Up is still proper.

You have now Set-Up the FL Die to P-FLR and will have the very best opportunity at having long case life and the very best accuracy possible.

 

[Poset]

Thanks guys.

I've read about PFLS, but somehow never made the connection.... I've been routinely necksizing until a problem occurs, then FL sizing, which always made me think I was potentially losing accuracy on one out of every every 3-5 reloads.

I'm gonna go to PFLS. Also going to look for Lee collet dies (something else I've read and heard about), especially since I use Redding dies now.

Much help - thanks again.

 

[rick smith]

If you are using Redding's Type "S" neck dies, you won't need the collet dies.Rick.