i use 444 marlin brass cases in my 410's i use large rifle magnum primers because i got a brick for free from a shooting buddy , i load 10 grains of herco with a .135 nitro card wad a .375 waxed wad and fill the case to about 1/8 inch from the top with 6 shot then insert a cardboard disc cut out of cereal boxes on top and put a drop of elmers glue on it and smear it all over the card with a tooth pick which seals the end of the case and keeps the shot in , excellent squirrel and rabbit load out to 35 yards