Experimental gunner operated, pylon mounted, M134 (minigun) on a Huey UH1-C. A 7.62 round isn’t all that large but at 3000 rounds per minute it gets the job done. Notably, I was qualified for 60’s and 50’s and sat behind both at one time or another in Nam. All. total I qualified with M-14, M-16, .45, .38, 60’s and 50’s.
Know exactly what you mean. Even sitting down on a bench at an outdoor range and shooting our old Wincester 30-30 rifle, I really thought I'd be on the ground due to the "recoil" affect after pulling the trigger. It definitely had a "punch" to it into my right shoulder!