in a technical sense, annealing brass implies taking it as far as it can go.
this is unacceptable for cartridge cases, because it will be too soft to hold pressure, and will have no springback to supply neck tension.
by definition, brass case should not be annealed, but rather partially annealed to get it into a condition suited to its application.
this condition is that it is soft enough in the neck not to split when worked, yet have some springing to supply neck tension when required..
from this softness in the neck, hardness should increase in a graduated way until the bottom 1" of the case is quite hard in order to retain its dimension under full pressure. the neck and shoulder should spring out and obturate to hold in the pressure, while supplying consistent neck tension from case to case in order to have low velocity standard deviations.
the case needs to spring back after obturation so that it can be extracted from the chamber.
at temperatures over 400 degrees annealing starts to happen, so we do not want any of the bottom 1" of the case to reach this temperature.
it is generally accepted now that 700 to 750 degrees will give the required partial anneal for necks.
application of 400 degree tempilaq to the base and not allowing it to melt ensures shooter safety.
700 0r 750 tempilaq INSIDE the neck should just melt, and then be removed from the heat source.
air cooling is sufficient under these circumstances.
done this way the partial anneal can be done consistently and in a controlled manner, a good thing for safety and accuracy.
obviously a machine is the simplest way to do this.
keep safe,
bruce.