The shot could be at the alleged ranged. Knowing the load would help determine that.
The gunshot didn't overload the mic, so you can hear it go off, and see when the moose first reacts. That gives you a time estimate based on the average FPS the shot was traveling over the course of the alleged distance (easy to determine with a ballistic calculator.)
So you could double check the range and it should be within a couple hundred yards, limited only by the fact that you cannot tell precisely when the moose was hit, only pretty close based on the reaction.
I think I measured around 1.7 seconds between audible shot and moose reaction.
1100 yards would be 3300 feet. That means the round would have had to have been traveling an average of 1,941 FPS. While a 1.8 second time just in case the initial discharge was muffled would put it around 1,833 average fps.
Obviously more initially and less at the end.
So after doing a search:
Found same video on you tube, with the poster claiming this is them:
http://youtu.be/cWAXQUCv8qo
They say it is "300 win. mag....McMillan Bros. MCRT"
You can search for the likely round, get the general details, and plug it into a ballistic calculator and see how long the round should have taken to reach 1,100 yards.
I would say that round lines up close with my earlier estimated average FPS.
Those rounds start over 3,000 FPS and it took about 1.7 seconds to reach the target.
Does that leave much room for error? He certainly would not have been catching up to it from that range if it had ran off wounded, and by the time he started tracking it, with his camera, little girl, rifle etc put away...
Probably not an ethical shot.
I found it interesting the video had the tag "This video has been age-restricted based on our Community Guidelines". It would appear hunting videos are not suitable for children anymore.