Ah, yes…I know I’ve seen a bunch of these.
The local shooting range does a bunch of training courses and the former military and contractor guys are way to into the Central Axis Relock and C-Clamp bullshit. They’re not any better shots for it — it just looks tacticool. The CAR “check your six” whiplash thing? Stupid. The over the barrel hold for rifles? Great if you don’t need those iron sights. (But the modified Rambo..? That totally works. Totes.)
Three things make you a good shot: practice, find the grip that works for you…and practice. Think about all those amazing rifle(wo)men and pistoleers across the last two centuries — their stances and holds were what worked for them — but in the end, they shot. A lot.