That shotgun-ammo video got me to thinking. The first shots he fires, he lowers the shotgun to cycle the slide each time:
This is a very common practice and can be seen with all manual types of actions on longarms...bolt-, pump/slide-, and lever-actions. Back in corrections in '97, tired of my shotgun quals sucking it (always passed but the score was unsatisfactory), I set out to learn why. Not even sure of the source anymore, as those were pre-internet days for me. At any rate, it was discovered that keeping the weapon mounted to your shoulder while cycling the action does a couple of things for the shooter. It helps you to maintain your consistency of position shot-to-shot. It allows you to stay focused on your target, which in turn allows faster followup shots. While I initially learned this for the pump shottys at the prison, it was relearned for the lever-action rifles. Watch how the Cowboy Action shooters speed shoot:
Bolt-action: http://www.youtube.com/watch?v=92Wrv_vpP4Y Pump:
And just for entertainment:
Jon