What is your opinion on running a leg drop mag pouch for four 5.56 magazines as an infantryman?

I personally hate leg-drop anything, whether it is for mag pouches or a holster. If you are looking to clear some pouches off your carrier, look at getting a battle belt. There is a wide spectrum of belts out there, but I would stay away from the type with a padded piece with molle weave that fits over a belt... the material will start to sag down from the weight. Make sure you get one with molle actually on the belt - I like the Blackhawk Padded Patrol Belt. Get some taco mag pouches for your weak side, mount your pistol on the strong side, and you'll be all set.

The bottom line about any kit set up is what is practical for you. Meaning knowing where everything is without having to look for it. The idea of a leg drop anything is not something I would recommend, yea you may look cool to the POG's (Fobbits) who have never done anything but when you're running and gunning you'll realize that you've made a mistake. Try different variations of how your kit is set and move it around until you can operate smoothly without to much interference.

If you don't want to/can't mount stuff on your vest, I'd suggest a MOLLE belt. Trying to pull mags out of a leg mag pouch is just going to be a pain because it will ride up every time you try to pull one out. Unless you have it tourniquet tight. I, personally, have been using a belt and I'm glad that I invested in one.

I had something similar when I was in the sandbox. But I had to modify it so it would not move. And then train how to apply it in combat. My suggestion would be go with something that’s a sure thing every time. Cause all you need is a split second of failure to happen. And it will cost somebody there life. Keep it simple it will keep you alive.

You're looking at trying to mount 4-5 pounds on your thigh. It is very hard to stabilize it when you run around.
The Army went through a phase were they issued drop holsters for side arms. There's a reason you dont see too may anymore.

I rocked a setup like that in Iraq for about two weeks. It chaffed the inside of my leg something terrible, and was not stable. In the prone, it was unusable, and mounting and dismounting vehicles it got hung up on everything, plus got in the way of the guys jammed in beside me. When running it flopped forward and aft with every step, adding to the chaffing. In the kneeling, it got pulled up on my leg, changing the angle and making it hard to access.

I ended up using the single stack three magazine holders side by side on my carrier, and a butt stock carrier for the 7th. The profile was low enough I could get down, but still easily access the magazines. It didn't shift from position no matter what combat pose I was in, making magazine changes easy muscle memory, rather than trying to fumble with an ever changing drop leg. Extra magazines went in an assault pack.

The idea sounds great, but the execution was a different story.

I don’t know about magazine carriers but I used a drop carrier for my pistol and it dove me crazy. Magazines, loaded, would weigh even more and probably rub a hole in your leg. If you are mechanized it might be better.

I personally don't think leg mag pouches are great due to the very high likelyhood of getting dirt and debris in it thus risking a breech foul, better to just stick it out with your ten mags on the chest rig.

Always carried four ammo pouches with 12/30rd mags, Cargo pockets provided drop space.