I recently attended a match where a portion of the stage involved shooting from the rear door of a helicopter fuselage using a sling for support. Essentially a piece of 1” webbing strung across the top of 5’ wide open door. I rested the back of my hand supporting the muzzle on the sling, barely on one knee with rifle shouldered and leaned into it a bit. Got it done, but that shit wasn’t ez. I struggled to hit my 300 yd targets as the front of the rifle rocked back and forth. It was hard enough doing this on stable ground, I couldn’t imagine being airborne. I was told this is a common shooting position when shooting from a helicopter so there must be some kind of special technique. Anyone got some tips on stabilizing the rifle in this position? Thanks.