GF,

I use 7 gr of 4759 with the Ideal 257420 in a lot of my .25-20SS rifles, from 44-1/2s through 044-1/2s to Low Walls to a Stevens Tip-Up Ladies Model.

I still anneal by the simple way I read in a book somewhere back in the Pleistocene.  Go to a resale store and get two cake pans of sizes that one will fit inside another without sticking.  Put a dot of paint in the center of the smaller one.  Put an inch of water in the larger one, put the smaller one in the larger one and fill with water sufficient to cover the shell base.  Put a shell on the paint drop, spin the smaller pan and play a butane torch just below the shell mouth as the pan and shell rotate.

Some people advise doing this until the shell gets red-hot, but I do it only until the purplish-brownish discoloration forms evenly from the mouth to the shoulder (if the case has a shoulder).

I still remember our 8th Grade Shop teacher telling us, as we banged out bowls and ashtrays from brass, that we needed to anneal our creations in the furnace every now and then, but not to leave them in too long.  This would result in what he called a "dead anneal," which made the metal as ductile as possible, but maybe so ductile that the next session of hammer pounding would tear the metal or thin it more than we wanted.  Certainly my earliest experiments in annealing cases to this red-hot "dead anneal" state resulted in squashed shoulders and torn necks when the shell was full-length resized or something more violent in the way of case forming was done on it.

So my philosophy is anneal often (if necessary), but only moderately each time.  I would think some of the zinc would be burned out of the brass if the thin metal got too hot.