The .577 T-Rex is NOTHING compared to the .700 Nitro Express.
http://airbornecombatengineer.typepa..._introduc.html
From what I understand, these are Safari cartridges, but anything bigger than a .700 Nitro and I'd expect you to be hunting tanks!!
Ever fired a 4 gauge shotgun? I can barely handle a 3" 12 ga. for more than 50 shells, I don't think I have the heart to try that with a 4 ga.
http://www.metacafe.com/watch/547250...ng_test_fired/
A bit of info on shotgun gauges.
http://en.wikipedia.org/wiki/Shotgun#Gauge
Say AL, you've been through Basic training haven't you?