Well, I have shot all these 8 rounds today. Recoil is pretty sensitive, but can't say deadly, it's o'key for me. The sound is something!
I can't say about velocity right now, didn't measure yet, but something go wrong. I spent 5 rounds for barrels "proof" and for recoil test and only 3 rounds for target shooting. 2 rounds from the right barrel - 1/2 yard between holes at 50 yards, all 3 rounds from both barrels are in aprx. 1 yard circle! Badluck!
I have to check all stuff and next time I'm going to shoot 8-10 rounds.

Geno.