I think most people would agree that on a production hunting rifle, its not worth it. Turning necks on a production rifle only increase the already large gap between the neck and the chamber. However, I have not seen an negatives from a large gap as long as they cases are annealed.
If you want the best performance out of your system, then neck turning is part of the process. Economical brands of brass are not consistent. I've seen much more consistent readings on Norma and phenomenal readings on Lapua.
The only time I've seen neck turning as directly important to accuracy is with WSSM necks. These come 19thou thick in 25cal, up to 24thou thick in 22cal. That much thickness leads to unmanageable tension variance.
But to turn them down to rational ~12-13thou means having your chamber cut for this. Otherwise you'd have extreme excess clearance..
Turning can be part of a plan for low clearance chambering, with a theme of producing and shooting very straight ammo.
Turning holds no real benefit (only potential detriment), outside of this.
For 99% of shooting applications, it is not worth the time in my opinion. I have a K&M neck turning tool and it works great for its designed purpose, but I just haven't seen enough of an effect to justify it. My non neck turned ammunition routinely shoots <0.5MOA, which I am perfectly happy with. I do, however, pretty much shoot Lapua brass exclusively, which arrives extremely uniform from the factory. Perhaps some other, less expensive brands of brass are not as uniform, leading to inconsistent neck tension, and in that case neck turning might be worth a look.
Much more valuable than neck turning, in my opinion, is annealing. I would recommend spending your money on an annealing setup before a neck turning one.
Way back when, I turned Win brass in my .243 for use in a production rifle. Seemed to notice a little better performance. The next production gun I turned Win brass for, didn't perform any better or worse. Win and Rem brass max variance was .003, Norma .0015, and Lapua .001. I agree that annealing is a more valuable procedure than neck turning.
When I buy economy brass, I do all the case prep techniques and get them very uniform. Almost as uniform as Norma brass. Thus, if you have more time than money, case unfirming on cheaper brass is a good option. The only case prep on Norma and Lapua brass I do is neck turn to get them all at the same number. I take off as little brass as possible.
I neck turn everything. Even high end brass shows its inconsistency when neck turning. You will see one piece that the entire neck is clean after turning and next piece will only be cleaned up about 90%. The main benefit that I have found is when combined with bushing dies you can control one of the most important key elements, neck tension. I run bushing dies with no expander installed. Running a bushing that will give me about .003 neck tension, then last step is I run a Sinclair NT mandrel which is .002 under bullet diameter through all my necks. I also anneal every firing. If you are looking to get low single digit SD's or keep ES to single digits consistently this will do nothing but help. Everyone has their own opinion of coarse. I have about 4 K&M neck turners along with drill adaptor. Once done I leave brass in adaptor on drill and polish neck up with steel wool inside and out. Best of luck.
I think Remmy nailed it. I turn for every rifle and use a .002" under mandrel to set the neck tension, but they all have tight necks because I ordered the reamer based on my brass. I agree that there is little improvement in factory chambers by turning, but setting neck tension with a mandrel would usually have a beneficial effect, if you use a quality mandrel die.
In a hunting rifle with more than .003” chamber neck clearance, NO. You would see no benefit UNLESS it was a genuine .25MOA or better shooter.
If this was the case, just a skim cut to get uniform thickness would only need to be done to improve uniform neck tension and annealing of the necks every other firing. I anneal after firing and before sizing.
In my comp rifles, I used to run neck turn only chambers, but often with certain powder/bullet combo’s I would get pressure problems from carbon rings/fouling, or whatever you want to call it, and then would be chasing my tail trying to overcome this. Very distressful to have this happen in the middle of a match.
After testing a barrel or 2 with larger clearance, going from .0015” to .003” or .004” total clearance, I found no negative issue on target and the pressure problems vanished. I still have to neck turn to clean up the neck thickness and clearance, but my aggregates have not changed.
Neck turning is like sizing, there are a million different views and none are incorrect.
Some turn well into the shoulder, some turn part of the neck length and others turn all of the neck length
I have a custom 22-250AI Model 700 VSSF II that is still less than .5MOA without turning Lapua SR brass, but will print into .2’s with a skim cut than it is so easy to tune that it shoots just about any combo exceptionally well. Some rifles are just flukes.
neck turning , IMO doesnt usually help on the first firing after the turning , because in order to turn it you usually size it , but once neck wall is trued up and fired . the next sizing is where it will line everything up
the problem with NOT neck turning, is you wont know if one or 20 are different than the rest , you may have 90% good even neck wall but 10% that need to be sorted out of that batch
Accurately a cast will be right but you can get a good measurement on fired brass,,the neck will spring back a little after firing but the chambers neck should be real close to .001 over the fired brass maybe .0015