Recoil is an inseparable part of shooting. It instantly affects how you engage the target. And the effects are amplified for machine guns. Each machine gun round changes the lay of fire. Gunners must constantly adjust to the recoil and re-engage the target. Fact is, training with recoil is critical.

Airstream forces work on the barrel of a machine gun poking out from a helicopter door or window. That 3 or 4 foot long gun barrel is a major windbreak. The airstream on the barrels push the weapon.  And, the faster the helicopter flies and the more barrel exposed to the airstream, the more torque on the weapon.