The thirty round GI magazine is a curved mag design in a straight mag well. It's not optimal. Cartridge followers get updated every 10 years or so to improve it's feeding reliability, and work better than the previous ones.
The metal construction is stamped sheet, which is ductile. If dropped loaded, on the feed lips, the precise shape can be deformed, and failures start up. They can be reformed, simply bent back, if you know what the proper shape is, and have a way to make it so.
In the service, many bad magazines wind up in the bottom of a supply box for just in case, and eventually are disposed in DRMO sales or stolen. There is no guarantee of what you are really getting when they surface. And if they are bad, they don't get crushed, they get sold to strangers at a gun show.
New Pmags are the solution, you know what you get, they are issue, the Marines bought enough that should be all they have in A-stan for combat use. The Brits are buying millions. Pmags don't bend when dropped on the feed lips, have the best follower, don't stick from dust and grit internally, won't dent in the side if stepped on. Polymer mags are clearly superior in rough use, and preferred in combat. Steel or aluminum GI mags still do ok, are cheap, and still useful for shooting. They are slipping in general opinion, polymags are that much better.
But, nobody makes then for the 6.8SPC. It's going to take more than 100,000 to sell 6 or 7 each to all that forums members, and the makers won't bother at those quantities. Apparently production costs are higher than we think.