JAM66,

As far as I know the only company making a 410 primer was Remington. they made a 209-4, but have stopped production. Talking to the folks in the trap club it seems pretty unanimous that the regular CCI-209 is the mildest of all 209 shotgun primers.

When I run out of 209-4's I will return to using Cheddite primers. I used them a couple of years before switching to the 209-4's and they worked really well. They might even be a bit milder than CCI

Do not get CCI-209M's...