35mm film canisters work well, used to have a 2 canister pouch with a belt loop a free bee from a camera magazine, which i used to put over the side lever on my m52 so i could not forget to bring pellets. at the moment i have a little camo pouch for some toy that is fitted with a plastic clip and i just clip it onto the trigger guard
also use some sweet tubes (smarties i think) that have cap that is attached to the body
when hunting or plinking i usually transfer 20-30 into the turn up on my tight fitting woolly hat, i find it a lot easier for cold hands to find a pellet there and it also stops them getting squashed and falling out holes in pockets etc, you look a bit strange but don't knock it till you try it (people who live in Florida or other hot parts of the world please disregard this)
fin