This is Saeed and his folks over in Dubai I believe. IIRC they are test firing a 577 T-REX on a round-robin sort of "give it a try" guy thing. Just guys having fun with a big kicker...probably one of Saeeds personal guns.
There's an entire series on the www.Accuratereloading.Com forum section...go to the bottom of the forums in Videos and select Champions I believe.
I guess even the internet is a small world. I got that link from a non gun (not anti related site and it turns out that you know these guys. I will have to check out those links later today. I thought it was hysterical that these guys would see the first guy shoot the gun and then try it themselves. Why don't they just swing sledge hammers at each other?
GRAVITY. It's not just a good idea. It's the LAW!
750gr solid at 2580fps yeilding 11100ft/lb at the muzzle, launched from a 13.5lb gun by 186gr of powder without a brake, 168ft/lb of recoil energy at 28fps ya that'll kick your butt.
And I'd love to give it a shot (pun intended)