Stan,
To get the results you are looking for, you are going to have to anneal the cases almost to the head. Note that the "almost" is very important, you don't want to soften the case head. A cousin of mine is making cases (65mm long) for a double rifle, from 9.3x74R. At first, he tried some 7x65R cases (I had previously recommended these on this board for similar rifles), but after trying every procedure we knew, he was unable to expand the 7mm necks to the necessary diameter without almost 100% of the necks splitting. The 9.3 necks didn't exhibit unacceptable losses. He did, however, have to fireform them several(3or4) times, progressively annealing each time, before the bodies completely expanded. After the initial fireforming he did the rest while testing loads, so it was not an unacceptably long process. The final result is nice looking cases. The annealing you need to do is for an entirely different purpose than the ones shown above.
Mike

Last edited by Der Ami; 12/07/23 04:46 PM.