You need a neck reamer then and not a neck turner. Why take brass off the outside of the neck when it is forming at the shoulder/neck junction? The doughnut will still be there.
Usually you only need to neck turn for a tight neck in the chamber or possibly to lightly true up the necks on some cases, but if it is all down to flow, it will just re-occur anyway as the brass flows forward into the neck. The errors in concentricity start back in the case body where one side might be thicker than the other and this simply extrudes forwards, so it will re-occur evetually if you just neck turn.
If you are worried about incipient head seperation use a piece of wire with a bend and run it over the inside of the case, you will feel it before you see it by which time its replacement time.
I have had 2 cases of head sep.
In .303 where I FL re-sized. Neck only prevented it and I assume the chamber dims were a bit generous as the head spacing was ok
In 5.56x45 where I swapped FL dies and did not set the new one up properly and over bumped the shoulders back. A Dillon gaugue soon showed the error and it was sorted.
I'm a maggot in another life you know
I'm a maggot in another life you know
You really shouldn't have this issue.
How hot are your loads?
All that brass comes from somewhere, I would double check everything you're doing before something seperates.
A man can always use more alcohol, tobacco and firearms.
.22LR CZ452; .22 Hornet CZ527
Tikka T3 Varmint .223; .204 Ruger CZ527 Varmint;
6.5 Creed Bergara B14 HMR
Fair comment.
I did not check the shoulder bump on my 5.56 NATO loads after changing over to another die and ended up with a separated case in a comp. I have had the rifle re barelled since and it has a different chamber profile (to allow for hot service ammo to extract easilly) which works well but again I have to reduce my bumping back/FL die setting.
I'm a maggot in another life you know
Why specifically would you find a dougnut in a cartridge and not say...a sausage roll? This demonstrates wonton lack of pastry control IMHO
I'm a maggot in another life you know