I have been testing this round for a while, now. Which is to say, gathering data here and there from my range trips. Thus far, it has proven extremely accurate, and the terminals I have obtained from milk-jugs mirror Hornady's claims. Namely, that it penetrates like a BEAST! It actually penetrated further/better than 62gr TSX 5.56. In milk jugs, the TSX load penetrated 3 jugs, and was found in the 4th. The GMX load penetrated 3 jugs and was found in the 4th, but I think it would have exited, had a 5th jug not been behind it, as it punctured the 5th jug and caused it to leak at the impact site!
Like I said, accuracy is outstanding, and POI is very near to M193, as my photograph shows.
All testing was conducted with my 16.1" Daniel Defense .gov profile CHF barrel with a Surefire 556-212 suppressor. The accuracy testing involved a T2 Aimpoint and G33 magnifier.
I will apologize, my typical 10-shot group is not present, but a 5-shot group of this consistency leads me to think that the round is very accurate, regardless of hair-splitting over statistical analysis thereof.
The expanded slug, fired into milk-jugs from 25 yards, measures 0.501" at the widest, and 0.39" at the narrowest. The narrowest reading is as taken between two opposing petals, and is an "extreme" measurement. If the slug were placed sideways in the calipers, instead of inserting the edges of their tips into these crevices, the narrowest measure would be 0.44". The height of the expanded projectile is 0.38" across the longitudinal center-line. Average expanded diameter, using the narrowest measurement, is 0.4455". Using a more common-sense and less "technical" narrowest measure, it is 0.4705". Considering the distance penetrated, quite frankly, this is VERY impressive!
*I tried to test Black Hill's 50gr TSX counterpart, but it shed its petals.