Neck size or full length size?

[6.5shooter]

Im always trying to fing ways of making my rounds more consistent and lower my velocity spread but this is one are im unsure about.

I run all custom border barrels in my rifles so factory chambers are out of the equation in this circimstance.

Im wondering if its better to full length size the case or just neck size it? Everyone that I have spoken to so far have different opinions. I personally just neck size at the moment but maybe I should be full length sizing?

I use redding comp dies for all my calibres and usually buy the comp seater, body die and neck bushing sizing die.

Then people talk about bumping the shoulder, does the full length sizing die always do this and how do you get the desired amount or is it a standard setting within the die chamber?

Im not sure as to which procedure is best for me.

Any thoughts?

 

Regards

 

Garry

[Laurie]

In a top quality barrel with a gunsmithed chamber, and using good dies, the odds are you won't notice any difference between the methods. Whether FL sizing gives you a little easier / smoother chambering depends on the cartridge design and the loads / pressures you're running. In recent years, despite popular myth saying otherwise most BR and similar precision competition disciplines see people FL size as they run hot loads and want flawless chambering and extraction.

 

Where FL Sizing can be an accuracy issue is in another issue you raise - shoulder 'bump'. In many cases, simply setting the die up in the press using the 'default method', that is bottom of the die body in hard contact with the shellholder on full ram extension, risks bumping the shoulder too much. That is setting it back too much from the fireformed shape and creating longitudinal clearance in the chamber. You're looking to set it back 0.001/0.002" from the fired position, just enough to chamber freely, but without any slop in the chamber. There are ways of doing this backing the die out and using the rifle chamber as the gauge, an easier way but one that costs money is to use a Hornady or Sinclair comparator body on calipers plus a case headspace gauge insert to measure the before and after sizing case-head to shoulder datum line distances.

 

Another sizing issue to watch is neck expansion during sizing, either get rid of through turned necks or minimum expansion work in the Redding Type S if you're using that through using the largest diameter bushing that does the job, so the expander ball barely kisses the inside of the neck - which should be lubed too. Too much work in this step and too much friction with dry walls can easily undo all the good work and expense of using top quality dies.

[6.5shooter]

Laurie,

Thanks for taking the time to give me such a detailed explination on this subject.

I always remove the expander ball from my dies and use 2 thou smaller bushings than the loaded neck diam.

I will stick with my original method of neck sizing at the moment and maybe have a play with the full length die at a later date by trying to bump the shoulder a bit.

My method seems to be working ok at the moment for the cartridges I load for which are 223, 220 swift, 6.5x47 and soon to be 6x47 and possibly 6.5x284.

Thanks again.

 

Regards

 

Garry

[kent]

Laurie,

Thanks for taking the time to give me such a detailed explination on this subject.

I always remove the expander ball from my dies and use 2 thou smaller bushings than the loaded neck diam.

I will stick with my original method of neck sizing at the moment and maybe have a play with the full length die at a later date by trying to bump the shoulder a bit.

My method seems to be working ok at the moment for the cartridges I load for which are 223, 220 swift, 6.5x47 and soon to be 6x47 and possibly 6.5x284.

Thanks again.

 

Regards

 

Garry

 

eventually you will have to full length size, the more the brass is blown out in you chamber the less it will contract back each time. I try and do as above myself but eventually............. Stiff bolt lifts will never be noticed if your cases become a "squish fit" and quick second shots get tricky also, recently i missed shooting the second of two foxes because i could no longer hold aim and cycle another round in due to some tighter cases that were getting overdue a FL