Great try at the reload drills! Keep at it, it gets to be fun, and automatic!
Aside from some already excellent points made here already, here's a couple of things you can introduce to make it even more challenging once you sort out some of the little things you are working on.
- Movement: Just like in video games if you stop moving someone will shoot you. So, pretend this is a two way range and when you have an empty mag or stoppage, move (shuffle quickly) 2 steps left or right. Do your IA or reload, then move back in front of your target and carry on the drill.
- Stoppage Inducement: If you happen to be shooting with a friend, have them load your mags for your. They can put in a dummy round, or two in each mag randomly forcing you to run your IA's and stoppages drills without you knowing when it will happen.
If you shoot with 2 people it gets even more fun, get a couple of targets, decide on a course of fire, ie, double taps on targets, two targets one round each etc... The game goes like this...
BANG BANG BANG click...
shooter one - Stoppage! (yell it out so your buddy can hear you!!)
shooter two - Covering!!
shooter two now finishes with his target(s) first and then covers your target either simply visually, or can drop rounds on it as well
shooter one moves, reloads and puts one round on target from that position then yells
shooter one - Ready!!
(lets your partner know your rifle is "up" again)
shooter two - OK!
acknowledges that you are back in the game.
Repeat for when your partner runs out or has a stoppage

Lots of fun
Obviously if you both just shoot off 5 round mags you will run out at the same time, so either induce stoppages, or the shooters loads fewer rounds in mags (5 in one, 4 in one 2 in one, that kind of thing) so both shooters get to run the stoppage drill and do the covering..
- More movement:

Try firing rounds as you are walking forward, when you run out of ammo, change your mag while maintaining forward movement and carry on the drill.
As mentioned, dump pouches are great for "administrative" reloads where you have a mag with a couple of rounds left in it.
Someone already mentioned the "change after 4 rounds" idea, this also works into a nice drill.... Have two targets, say a metre or so apart. 5 round mag, stand in front of a target, fire 2 rounds, move to your left, or right, wherever the next target is and fire 2 rounds.
You now have one round left in your chamber, do you:
a) reload and have 6 so you can do three more sets of left target right target
b) move to the next target and fire one round and practice a reload drill? (move 2 steps then reload, move back and fire the next round)
Up to you, but you can play with it to practice moving and reloads at the same time.
EDIT: Please do any of the movement stuff carefully so if you are shooting with someone else, no one is moving ahead of the others muzzle.