Jock -
I was just thinking -
when you are going through your presentation, from step 4 to step 5, you are driving the gun straight out to the target. Like a bayonet. you are not coming up at a angle(bowling), nor are you coming down on the target(casting/fishing)
the same should hold true on a mag change - why would you point the muzzle up and come down on the target like casting, which is incorrect presentation, and will cause being off target
as a mattter of fact, instructors point this out as a cause for you being off target -
also - in all honesty - i have mistakenly held the gun at a slight angle when doing a emergency action drill. the mis-fed round (a stove pipe IIRC) didnt clear and I began to shake the gun to clear the round - I was immediately stop, and correct. My my instructor told me "let gravity do it's job. the round will fall if the weapon is parelle to the ground. if the weapon is at a angle, the round can easily get caught up"