[oldmanFCSA]

Use a torch with a blue flame on the shoulder upwards to neck.
Do so in a very dark room but light enough to se what you are doing.
When the neck area out-gasses an orange cloud, proper annealing has been completed.

I built a rotary device using a cake-pan to hold and rotate a 50BMG case.
It takes about 13 seconds depending on size of your torch tip.
I test the rotation speed on scrap brass, then fine-tune as the lot runs.

Recently, a friend bought an AMP (Annealing Made Perfect) machine and we are testing/using it extensively to acquire consistency in our annealing processing.

Y.M.M.V.