Whenever you're ready suka! 

I'm not Suka, but pop off the upper receiver and load it up.

yo eric! you should definitely use a pmag next time because i dont have any tightness issues when loading up to 29 rounds into mine. i think youre having trouble because the sleeve you made is pinching the magazine a little bit. mine is as easy to load as a magazine that is not inserted into the mag well.

I'm not Suka, but pop off the upper receiver and load it up.

suka's been dropping hints about a modification for loading without popping the upper.

PMag base plates are pretty easy to remove.  Pop off the base plate, pull out the spring/follower, drop in your rounds and reassemble.  Of course that spring is going to be under pressure so that might be a challenge, easier if you don't top it off.  Maybe use a 40 rounder and load only 30?  Probably less hassle to just tilt the upper and load from the top.

PMag base plates are pretty easy to remove.  Pop off the base plate, pull out the spring/follower, drop in your rounds and reassemble.  Of course that spring is going to be under pressure so that might be a challenge, easier if you don't top it off.  Maybe use a 40 rounder and load only 30?  Probably less hassle to just tilt the upper and load from the top.

I just tried this. With more than 10 rounds in there the spring has to compress so much that's it's pretty difficult to get the base  plate back on.

How about modeling it after the S&W M&P 15-22 magazines where you can pull the follower down to help ease with the loading?

the difference is, instead of loading at the top of the mag (where the lips are) you make a cutout on the side of the lower receiver, or mag shell, that is just big enough to fit rounds.

loading up the rounds would be easy.  you just pull down the follower with your thumb, and pop rounds in from the side, then release the follower so the tension is added back onto the follower.

How about modeling it after the S&W M&P 15-22 magazines where you can pull the follower down to help ease with the loading?

the difference is, instead of loading at the top of the mag (where the lips are) you make a cutout on the side of the lower receiver, or mag shell, that is just big enough to fit rounds.

loading up the rounds would be easy.  you just pull down the follower with your thumb, and pop rounds in from the side, then release the follower so the tension is added back onto the follower.

That's pretty much nailed it.
Drill a hole on the back of the mag. large enough to drop rounds in.
Attach a pull string (cable) or rod to the follower and extend it out through the floor plate.

To load, pull down , drop rounds in, release.

I'd recommend 20rds mags. Since they are straight.

Or a

Slide on the side of the magazine.

Slot the mag on the sides , attach a "puller" to the follower.

Basiclly, it slides the follower down and just drop in the rounds as above.

I just tried this. With more than 10 rounds in there the spring has to compress so much that's it's pretty difficult to get the base  plate back on.

Seems like you could fabricate a loading sleeve that would allow you to compress the spring more easily.  I envision it looking like a basic mag loader... hollow elongated rectangle with a "tooth" over the end.

one way that might work is putting the hole (for inserting the rounds) near where the follower bottoms out in the magazine.  this way, when you release the tension on the follower, the follower passes the hole and prevents dust/dirt from getting into the magazine, and prevents rounds from falling out of the magazine.

my other idea would be to cut the side of the lower receiver and create pivot points on the front and back of the magazine shell that connects to the front and back of the magwell.  when you want to load up the mag, you would disengage the magazine and rotate the magazine out.

in a sense, this would be like turning the ar pistol into a sort of revolver-type mechanism.  the pivot points would allow the magazine to maintain the right height so that the loading mechanism isn't affected when the BCG picks up another round to put into the chamber.  the only problem with this design is that you'd have to maintain the structural rigidity of the lower.  this means that you'll need to create a swinging door mechanism that would hold the magazine in battery, and provide some kind of cross-brace to make up for the metal removed.

this would facilitate faster loading, but would be a slightly more complicated design.

could this mag be utilized?

Make it removable! 

could this mag be utilized?

Sure