Partial neck sizing?

[762shooter]

Regarding full length sizing, partial neck resizing, sizing to die just touching a smoked shoulder or an actual neck sizing die.

What are the pros and cons with respect to accuracy (first consideration) taking into account not buying new dies, easy of the process or anything else to consider?

 

[Ganderite]

I use two different techniques to neck size.

A neck sizing die does the job but the button tends to stretch the case. In some calibers I use the decapping pin/button of a smaller caliber, so the neck is left very tight. In some calibers/powders this has noticably improved accuracy. No need for a crimp if used in a semi auto.

I use the Lee collet neck sizer. This squeezes the neck down onto a mandral. No case stretching.

Another advantage of the Lee collet is that the die body cavity is quite large, so if you have an Ackley the parent caliber Lee die will neck size.

I only use the FL die to neck size if I have a caliber/rifle that requires a slight shoulder bump for each loading. This is a bummer because it means the cases have to be lubed and then cleaned.

 

[kombayotch]

I think every serious rifle reloader should have one of these:

One of neat things you can observe is how the datum point actually moves forward when you partial neck size with a FL die. This happens because the case body and the neck are both under compression, causing the shoulder to bow. So, you end up with a case shoulder thats longer than your headspace and being compressed when you close the bolt. This is the pitfall of partial sizing with a FL die. Brass doesn't start to flow forward until the shoulder makes contact with the die (then its FL sizing).

With a large factory chamber, neck only sizing can be beneficial for accuracy and case life. But, with a tight match chamber, unless you're shooting benchrest, there isn't really any significant accuracy gain. Proper neck tension does a lot more to improve groups. Note the dies he is using (FL bushing dies):

http://www.6mmbr.com/gunweek084.html

I don't neck size anything. FL sizing give me more reliable feeding and more consistent velocities (loading-to-loading). Adjust the die so that you're bumping the shoulder back only 0.002-0.005" and you're gtg with the FL bushing die.