Ouch! It hurts just watching this, especially having myself fired the Safety Harbor 50 Caliber AR that Ry loaned us last summer. The 70+ year-old who’s firing it didn’t get the buttstock on his shoulder, so it slid under his armpit from the recoil, causing the optic sight to clock him in the face. That’s a heavy rifle moving back at him at a good clip. He was OK, after he stumbled to his feet and I was able to get him to reply to questions. Notice the image blur as the shock wave (usually referred to as “muzzle blast” but in this case I use “shock wave” as a more descriptive term) hits the camera. Also notice the gravel being hurled back and to the sides from the high-pressure jets coming out of the muzzle break.
Firing the little .50 BMG “carbine” with a proper hold feels about the same as firing a magnum load from a 12 ga. shotgun. Quite nice, really. Its all about style.