fyrepowrx,
Out of my 22" Virgin Valley Contender barrel I get 3,350fps using a 70 gr. bullet, and 3,100fps with an 87 grain bullet (using AA2460 powder).
E. Arthur Brown makes 30 Herrett brass and sells it for a reasonable cost, so the further forming that is needed to make a 25 Classic is much facilitated. Cases can be made from common 30/30 brass, but the process is more elaborate. Not hard, just time consuming.
Lefty