12 December 2022
I don't remember a head to head comparison of turned to un-turned brass and jb's. Seemed like all custom chambers were tight by design. Bud gave the textbook answer for turning brass and Steve was right about using graphite.
Neck turning to control tension has been given the kabach by others including Bottiger and more recently John Alexander in his recent article in TFS 279. As he put it:
“Apparently, this is just something that some reloaders believe they have seen or just know is important because it sounds logical.”
I think many would agree that the only reason to turn a case is for alignment to the bore. However the accuracy improvement with neck turning is dependent upon the equipment being used isn't it. Bud said he turns to at least 75% cleanup, discarding the outliers and he is turning neck thickness of .015. I fully agree. This is logical, easy and even fun to do.
But a custom action, reamer, barrel will benefit more from neck turning then a production rifle. Right? So from the low end of the spectrum, that being a production rifle, how much is there to gain from neck turning? I guess that last question can never be answered. Every over the counter rifle has the potential of having a variation of bolt face to bore alignment and the degree of benefit truing up the case neck will bring.
It is possible maybe even probable that cleaning up the necks to .015 will improve accuracy. It is also possible that the alignment is so pathetic on an over the counter rifle that even truing up the neck won't even help.
For some it just isn't going to help much is it. For others, turning necks for production rifles even those having oversized chamber necks will put the bullet closer to the center of the bore. For the time being I'll continue neck turning just because I think its the right thing to do. Guess that makes me guilty of what John describes as doing someting "....because it sounds logical".
I asked a question earlier and if anyone has any reference to it I am curious what measure cast bullet shooters use for tolerance when describing a tight neck chamber. And yes I do miss the magazine Precision Shooting. But we do have the TFS on CD. For people like me that helps. Thanks, Bill.