Its not trash talking to point out that salt bath annealing does not work for rifle case necks because the rate of heat transfer is too slow, and the end result is a case with too soft a shoulder and maybe the body too.
Anybody want to by my Salt Bath Annealing tools?
Flame annealing has enough energy applied to the correct part of the case - and assuming you calibrate with Tempilaq for every run (because gas settings are touchy!), the results are 'good enough' at a 'reasonable' cost to achieve, for the purpose intended. To be clear, thats gas annealing with a time controlled system that repeatably produces neck temperatures at or above 450F in the neck to shoulder area while the same case does not exceed 750F from shoulder to body.
In case you want to make life a lot simpler turn your case necks to whatever thickness removes 1/2 of the variation in case neck thickness - its a one time investment in reducing runout and centering the bullet in the barrel, typically by a couple of thousandths offset.
Once the case necks are a uniform thickness (1/2 the variation in thickness removed which oddly works out to about 0.011" neck wall thickness in most of the cases I've turned regardless of brand for 204 Ruger, 6.5 Creedmoor, and 308 Winchester - might be different [less than 0.011") in 22-250 and other old case designs), you can choose a neck size bushing that produces 0.002" neck tension (or some other number), and never ever have to push or pull a die through an unsupported neck - which is a significant source of runout.
Think about the geometry inside the die as the case is being withdrawn. The sizer ball can easily drag the case neck out of the near perfectly concentric alignment the sizing operation imparted.
Another benefit of neck thickness uniforming and only neck sizing enough to hold the bullet is that you will likely not have to trim your brass again, or if you trim it to 0.010" shorter than the actual chamber neck length, it may not grow enough to worry about during the life of the case. BUT ALWAYS CHECK!
If you find that you have to resize the case body, I have setup a 5.56 NATO Redding Type S with a 0.247 bushing that works well in my Dillon and by setting it to bump case shoulder 0.002, there is very little case neck length growth. But since I have the time and inclination, I use a Frankfort Arsenal (similar to a Gracy) neck trimmer to set the neck length from the shoulder before the case enters the Dillon.
I do all of the case neck machining after annealing (why work hard brass when you could work soft brass?)
It has been a while since I've updated my notebook, but a lot of this information is included in it. I think I may have to write up the Dillon this fall …
! Done 6.5 creedmoor, 308, 223, 5.7x28, and 7.62x39's. Amongst 9mm, and 45acp. About 10,000 rounds in! So mainly torch angled edge and up, 3 to 5 seconds before it turns cheery red to release neck tension and hardness, watch for not discoloring anywhere near base, then fl resize to harden it again before seating bullet. Just that it will only barely harden and that's what u want for consistency and accurate loads! Did I get that right?
