...Results - Transition to pistol beat the rifle reload fairly 100% of the time. the only time the reload beat the transition was if the pistol man screwed up on the draw.
100% the way we trained in CQB while in the Marines.
INSTANTLY DEFAULT TO PISTOL.
Less accurate fire, but will keep people from moving in on your position while you reload.
One way we use to get insurgents or inexperienced fighters to show themselves was to fake a reload.
Stop firing, look at the side of the rifle, even drop the mag into your off hand,
Then snap it right back into place when the opposition started to move since they through they had 10 to 15 seconds before you were active again!
*IF*...
You are covered by partner, and not under heavy fire, reload the rifle since it simply has greater accuracy and stopping power,
But if you are in the heat of a firefight, by all means default to pistol until you can reload.
What happens many times in battle is everyone shoots at once (despite training to the contrary) and you all wind up reloading at the same time!
SOMEONE, ANYONE should be laying down suppression fire, even if it's a handgun to keep enemy from moving on you during that reload cycle!
I know of at least one instance where insurgents were counting shots (More or less) and made the mistake of moving against what they though were 'Rookie' troops when the fire stopped for reloading of two or three they could see happened all at once.
They quickly found out that a Delta Drum was in operation, and they were COVERED.... last lesson many of them ever learned!
Empty or not, take EVERY break in shooting to change mags!
If you have fired even ONE round out of the mag, practice cover fire teamwork, one covers while the other reloads!
Above all else, PRACTICE DEFAULT TO PISTOL!
You never know when your rifle is going to fail, and your zone MUST be covered!