D800 in 12g trap load

[oops]

I bought some of the happy powder D800 from Canada ammo.My main issue I am having is I do not have much shot gun loading experience to determine a " hot load"...

To date I have followed the 10% less rule.The only thing I have been noticing are what I consider more the normal primer flattening when compared to a factory round and felt recoil.

Any hints?

Cheers

 

[Maritime Storm]

From what I've read it is similar to 800-X, which wouldn't be my first choice in a 12ga Target load powder.