you are correct as I did not want to make the video too long. I also wanted to give myself an advantage by using a lighter weight bullet knowing that a real life scenario it would probably be a 115 or 124 grain bullet used.Nice demo. I realize your are shooting fast in order to keep things interesting, but you'll do better when trying for distance with a long gun if you practice some fundamentals on breathing. 3 seconds in-3 seconds out. Doing that three times between each shot will definitely help with accuracy. You need ya a shooting bench.
I've shot my AR9 pistols with 5" barrels out to 100 yds(our longest range). I get about a 4-5" group off a rest and about a 10" group off hand, standing. Drop on a 147g hand load is 10-12". If I aim at the head on a 50% silhouette, my shots drop in at center mass.
I've only shot that ammo twice in my life. The first time was a Calvert Deputy that had an FN 5.7 which had some serious muzzle flash and the second was an AR conversion that kept jamming. Those along with the availability and cost kept me away.I heard and read the 5.7x28 is superior to the 9mm in every way except cost.