RE: .410 for Survival
A lot of flares I've seen, in any gauge, could only be used in certain barrels, because they are harmful to standard barrels. I have seen .410 flares, and they are rather weak, they don't last very long that is. Why would you need flares anyway, why not use rule of three?? just as effective as flares, and if you're in brush, no one is going to be able to see up unless they are in a clearing, but sound will travel very well.
Screw the 10 ring, keep them in the zero!!!