Neck Turning for Factory Chamber
Neck Turning for a Standard Factory Chamber
I have read many times the statement that neck turning is a waste of time for standard factory chambers.
Well it depends on how you do it .
First you must study up and learn how to turn an accurate case neck.
When you have mastered that you can apply the sizing system outlined below.
You only need to skim turn the necks to an 80% cleanup.
There is no denying that turning a case neck for a factory chamber will increase the clearance between the case neck and the wall of the chamber, but you can retrieve this clearance for a section of the neck to a tighter fit than before turning .
With partial neck sizing and body die sizing .
The idea is that you leave a portion of the neck , about one third of the length from the shoulder , unsized at all times.
To achieve this a bushing type neck sizing die or a Lee Collet neck sizing die is used to size the neck only . To shorten the length of sizing in a Lee collet die place a machined washer of correct thickness over the case and between the collet skirt and the shell holder .
This section of neck never gets sized that is why it must be kept short .
If it is too long it can make chambering difficult and there will not be enough sized section to hold the projectile concentric and secure especially in short neck designs like 243 W .
A body die is used to size the remainder of the case when necessary and it doesn’t touch any of the neck .
This way you gain some of the benefits of neck turning , without the disadvantage of excessive neck clearance in the chamber.
This is a technique for a bolt action rifle that has already shown to be accurate and you want to improve it .
It is definitely a waste of time employing this idea in a rifle that doesn’t shoot well enough to see any small improvement in the groups.
Other methods such as pillar bedding , hand load development , quality projectiles etc, would be more likely to improve the bad shooting rifle .
So work on everything else and when you run out of things to improve , it may be the icing on the cake .
There is no one system of anything that suits every rifle , the secret to performance is experimentation.
Some rifles brake all the rules such as shooting better with Full length sized cases than Fire formed cases.
Things like this can usually be traced back to some inaccuracy in the original manufacture e.g. crooked chambering job.
It's your job to figure out what works and what don't.
This article is designed to help you think about ideas you may not have come across before.
I have been using this system in some of my rifles for many years and find it improves accuracy .
Written by John Valentine. 25 / 10 / 01. Copyright.
