Quoted:
The only problem is for anything other than casual use, they couldn't be made durable enough unless the locking points were metal lined. Metal v. plastic holes or tabs...metal always wins. The locking points would become worn, creating magazine wobble which would soon lead to malfunctions.
This has been my experience with Thermolds. They fed VERY smoothly...but the front locking tab begins to stretch over time.
Now, to counter that, Magpul uses one HELL of a great plastic.....it is very possible that it would not be an issue with a Pmag.
It seems to me that by the time you could engineer a manufacturing process that could mold metal locking point tino a P mag body the manufacturing costs would end up being prohibitive......though Lancer seems to be doing okay with their molded steel feed lips. That being said, my experience with thin things molding into other thin things has never been very positive. I could go on about this, being in the automotive industry but it would be rather boring to most. Suffice it to say that I'm not a fan.
Still, Magpul....if anyone could pull it off and make it work....it would be you guys.
The gorgeously smooth feed of the Thermold M14 mag is tempting to try to achieve if you can exceed the Thermold's limited longevity in the M14 platform.