I start by annealing the .30-30 brass, and go straight to the .250 die because I don't have a die in between. I run the cases in incrementally , wiping and relubing each time- with minimal lube- until fully "sized", so as to minimize oil dents in the shoulders. Then into the HP die, again incrementally with as light a film of lube as possible to minimize dents. A long drawn out process that takes like an hour to generate 20 cases, which would be dramatically lessened if I weren't too cheap to buy proper forming dies, or some other intermediate dies. Even then I can usually figure on losing 10-15% of the cases in the process.
I gotta trim the ones made from .30-30 brass because they do stretch a bit, but not much- I could probably use them as-is. I don't trim the ones made from .25-35s except to square up the case mouths.
The best batch of brass I have are some old Western .22HP cases from the 30's, I'm guessing. I took them out of a sealed box of 25 recently. They mic .418 at the head, and didn't stretch or swell one iota on the first firing. With annealed necks, I'm saving them for "special occasions", such as an upcoming tiger hunt, or the zombie apocalypse.
If I had to say one piece of advice for any .22HP experimentation, it wouldn't be about bullets or case forming techniques, it would be to throttle back your loads to extend case life. No need to run full speed and end up tossing cases after only a couple loadings. 2000fps bullets will punch the same size bullet holes in a paper target as the 2600fps ones do, and more often than not in smaller groups too.
