A couple thoughts, Jerry is a world champion shooter. He does a couple things that I don't think the NZ shooter had, a serious muzzle break, and he also shoots a lower energy projectile; both for better control.
*Note the amount of travel the go pro has, with any recoil, the body will move quite a bit, and overly exaggerated on camera. It looks like the NZ footage is off of Dtube now so I cannot compare.
*It's just my opinion, but the NZ shooter looked to have a larger caliber'd AR platform, perhaps 300 blackout, or something; which would hit a little harder. *I don't know if this helps anyone decide on the NZ footage real, to not real, not sure myself, but what is sure, is their attempts to hide the video, while making decrees that 'laws will change', seems very hypocritical; it's in league of 'do as I say(just cause), not as I do.'