Looks like a tube scope (pick your favorite) and a JP Rifles handguard
with a rail segment attached and some kind of dot on the rail. Based on that and his handgun, this is an "open" division shooter.
I just poked around the video host site for you. The rifle in the video is detailed here
. Nothing really wrong with what he is doing, except it is an open rifle, and his personal preferences abound (like, a long stock). The 18" barrel is common in 3-gun - great compromise between rifle and carbine - better handling than a 20" with comp and more velocity than 16". I would have an 18" barrel with a JP handguard if I did it over again.