Umarex Hammer Big Promises for Big Game?

Okay so I've been looking pretty hard at this gun and fingers are twitching to hold her. Got a few reservations though. 
first is the 50 Cal part, that is a lot of lead to be throwing down range and I can't help but wonder of it isn't going to be like watching a cannon ball fly through the air.
The specs shows 1100 fps for a 250 grn bullet and 600 fps for a 500 grn, when you consider 1/2 inch diameter bullet 250 grains isn't going to be very long in fact it will almost be a round ball, my black powder 50 Cal shoots .45 250gr sabott and they are copper jacket rounds the lightest .50 lead that you can find is 300gr in what would be considered a actual bullet and not round ball. 
Another factor that caught my attention is two shots at 50 yards one inch group.... Okay soooo why are you only showing stats for 50 yards.
Now don't get me wrong I'm not banging this gun I don't know anything but what the stats are saying/promising. So I honestly do not know what kind of real field stats are going to be. 
fps is kind of a weird science to me, from my limited experience there are multiple thresholds once a bullets goes above or below those thresholds it reacts to outside forces differently drag for example is not consistent but compounds. 
Another item that caught my attention is the three safety functions one is it will not fire without the clip installed so this means that you have to stay within the bounds of the clips size no hand loading. 
This is a moderated valve at 3000 psi and a carbon fiber 4500 psi tank (like) and has a good A.R form factor furniture (like) and a updated rail that is compatible with today's optics and other nice toys (really like) 
So what do you think?