Author Topic: Neck turning (Read 320 times)

Rum River · « **on:** January 24, 2006, 03:51:21 AM »

Thinking of trying neck turning on my varmint calibers. Am looking at the Forster products.

Question: Would I be sacrificing precision if I use the hand-held tool vs. the case-trimmer-mounted system?

PaulS · « **Reply #1 on:** January 24, 2006, 06:59:39 AM »

neck turning is used to make the neck of a standard cartridge fit a small or target chamber or when forming small caliber cartridges from larger ones.
Neck turning will do nothing for accuracy if your cartridge already chambers. It is possible that turning necks down will make your loads shoot larger groups than they were shooting with standard cartridges.

Ka6otm · « **Reply #2 on:** January 24, 2006, 07:37:32 AM »

Actually, there is one more use for neck turning, and that is when the neck thickness varies more than around 0.001" on a particular neck.

Ka6otm

victorcharlie · « **Reply #3 on:** January 24, 2006, 07:51:52 AM »

Brass will flow from the head of the case to the neck. Depending on the cartridge, and the load this can happen rather quickly, or very slowly. One sure way to tell is to take a fired case and see if a bullet will fit in the case before sizing the case. If the bullet won't go, or goes tight, then the neck needs to be relieved some. If the neck thickens, and you seat a bullet in it, then it can be difficult to chamber the round, and because of the pressure from the thick neck being squeezed into the chamber higher than normal pressure can result, even if using a load well below max. If you have a cast of the chamber, then you can play with the neck thickness a little using the chamber dimensions minus the clearance, usually .003".

When the neck thickens, you can either outside turn the neck, or inside ream the case. The benefits of one over the other has been debated for some time now.

I see no reason that a hand held unit, for all practical purposes, can't be just as accurate as a fixture provided you take your time.

You could always check the runout with a v block and a dial indicator.

Pauls is right, if the neck is not turned cocentricly (did I spell that right?) then accuracy can suffer.

Wilson makes a real nice hand held inside reamer that uses a die to support the case. If you have time and can afford it, you might want to give reaming a try as well. Some get good results with reaming and it might be a little easier. JMO.......

Lone Star · « **Reply #4 on:** January 25, 2006, 03:29:06 AM »

Like PaulS said, neck turning will have no positive effect on accuracy with standard cases and standard chambers. It will increase the radial clearance between the case and the chamber - instead of decreasing this measurement which is what custom target rifes do. This increase in clearance will offset any tiny accuracy improvement which the turning will do through equalizing the neck thickness.

Depending on the sizing die dimensions, turning the necks may reduce neck tension on the bullets and allow them to move within the case during handling or cycling from the magazine - not a good thing for accuracy. IME the case-trimmer neck turner will not equal the precision of a hand held instrument like the Sinclair. But since turning the necks will do nothing positive for accuracy anyway, it really doesn't matter.

OTOH, if you are forming .22-250 cases from .308 brass to obtain thicker necks (as I have) then you can see better accuracy by turning. Turn the necks so that they have about 0.002" of radial clearance in the chamber, resulting in a "tight neck" chamber and better potential accuracy. This is a lot of work though, and even then the accuracy improvement is small.