Factory mags from main gun makers (and Mec-Gar Italian ones made for and marked with main gun maker name or sold under the Mec-Gar name) are typically PERFECT to begin with.
Exception: cracking of early CZ Scorpion mag feed lips, which were replaced by CZ USA for free.
So no second party feeding, lockup, ejection, load capacity problems, no 2nd or 3rd generation incremental “improvements” (how do you keep track of what gen you are dealing with?), no persistent ProMag disasters, no “improved USA made AK magazines - haha, what a concept!”.
So I am bit leery of aftermarket mags.
Or for that matter any aftermarket device that somebody made and sold without putting it through comprehensive and extreme testing (e.g. extremes in environmental temperature that police and military grade equipment requires). That can create unexpected problems: friend of mine put two rounds through his hand after an aftermarket front grip suddenly released when he was shooting his transferable UZI. Fortunately bullets missed major nerves, vessels and bones in his hand. Hand surgeon cleaned up the wound nicely and it healed without any deficit.
