300-MP is Alliant's answer to H-110/Win296. Those powders give better hull life than Alliant .410 and 2400, or Hodgdon Lil-gun.
Downside is use of higher charge weights and dust sized powder granules migrating everywhere through your press.
HS .410 hulls give better hull life than old CF AAs. First time loading them didn't lose one case until I'd passed 12 firings. Internal capacity is also greater, so it's much easier to get the max NSSA shot charge to crimp.
Having a several lifetimes supply of the old hulls, so use: 14.6 gr 296, .410 AA/Yellow Duster/Orange PC, Win 209, #9s. 1240 fps. Sometimes substitute Fio 616 which ends up at 1200 fps.
