Dan,
Until there is some sort of consensus on the strength of the new EEA double rifle, about all a guy can do is use something conservative. We do have a SAAMI-pressure compliant 45-70 GOVT load that pushes our 420-grain SuperHardCast Hammerhead to 1650-fps from 22-inch barrels. It's hard to imagine that EEA would produce a new gun incapable of handling a SAAMI-pressure compliant load. But again, it's hard to be definitive about something that the industry has not spoken on, and something that we have not had a chance to evaluate ourselves. As to performance, our 45-70 GOVT Ammo is extremely effective as can be seen by reviewing our Trophies Page.
Cordially, Randy Garrett