What is the minimum temperature required to cause brass to anneal?

Is it better to allow cases to stretch to the maximum trim length and trim, or is it better to trim to the minimum trim length every time.

Thanks in advance
ZM

The grain of 70-30 brass, which is the brass used for cases, doesn't significantly alter until a minimum of 572 degrees F. The ideal temperature for the necks of cases is between 680 and 700 degrees. Annealing continues to 1400 degrees, at which point the brass is completely annealed and is useless.

How often you trim depends on how much your cases stretch. Some guns and loads might cause cases to need trimming every couple of shots. Mild load in a tight chamber might do ten shots.

I would suggest that you check ten cases out the batch you are getting ready to reload. If even one is at max, trim the whole batch. If not, not need to trim just yet.

I only trim three times before discarding the batch. That brass is coming from somewhere and I don't want to find out just where.