I use a simple torch and roll the case in my fingers for a fixed time, at a fixed position in the flame. Certainly not the most sophisticated or consistent method, but it prevents split necks and neck tension is consistent enough that my groups and velocity dispersion are small enough for my needs.
If you loaded 1000 cases and annealed them with this method, why not just spend a couple hours at work and the overtime pay would allow you to buy 1000 rounds of brass and just keep reloading and throw away the cases when they get a split neck. It would save enough time and the accumulation of brass without split necks would give you enough brass, you could let them fly out on the ground and not even pick them up.
https://www.24hourcampfire.com/ubbt.../re-once-fired-fc-223-brass#Post15773699
