I could, but honestly they are so cheap it would not be worth my time.
https://www.midwayusa.com/product/966347/magpump-polymer-magazine-loader-polymer-unloader-ar-15-223-remington-556x45mm-300-aac-blackout
I mean at $150. I would have several hours into making something work. It's a no brainer.
That was at the link I posted and you can get it in plastic or billet aluminum. But DanPatWork posted the the other one I was talking about. You literally dump the ammo into the hopper and the machine sorts it out. Put in a 30 round mag, punch in 30 or a lesser number on the controls, wait a moment and you're done. Whatever your magazine capacity is you can load it completely full or less.
I use a 10 round Thermold mag charger to load all my army surplus AR mags. You can use G.I. metal stripper clips, Thermold plastic clips, or no clips at all. I have maybe 360 rounds in Thermold clips in case I need to load in a hurry, but normally just use loose rounds. I put the loader on the mag, put 10 rounds in, jam them in with my thumb, and repeat twice for each mag. It's impossible to load the rounds backward so it's idiot proof, but nothing in the world is *&^%$#@ idiot proof, if you know what I mean. In an emergency you can burn the clips for fuel. They're smokeless and non-toxic, so there's no problem using them to heat food or water. It's $9.95 for a loader and $4.95 for 10 clips/fuel sticks. For 5 cents more you can get the combo pack, but I wouldn't. A nickel saved is a nickel earned. The clips can be reused a lot more times than metal clips.
This guy makes it look hard, but for me it's easier to load loose rounds by putting the tip of the bullet in the loader before I put the base in. You don't have to line up both ends at the same time that way. You can tell the loader is filled with 10 rounds because another one won't fit. Clip or not, I put the base of the mag against my leg or on a table, use the joint of my thumb, and press down hard and fast. Done. A solid rest is better than using your other hand.
https://www.youtube.com/watch?v=CEHPHnmod3E http://www.thermoldmagazines.com/mc-m-16-ar-15-10/ http://www.thermoldmagazines.com/sc-10-223/