@Even Steven - I spent some time comparing magazines today under a strong light and using a 3.5x magnifying hood. It looks like the USA mag may have been stamped with old tooling or something. The Italian ones all look "undercut" on the inside, leaving a thin crisp edge and making the metal actually look thinner even though it isn't. The USA one looks thicker (even though it isn't) and maybe even tapered toward the outside. The shape of the "back" of the notch is also rounded and kind of overcut on the USA mag.
Next I tested Italian mags against the US one to see how far down the mag release had to be pressed before they would release. All mags were full. At first it looked like there was no difference, then suddenly the USA mag released noticeably earlier a couple of times in a row. I finally was able to narrow it down to the USA mag releasing early if one was pushing the release toward the back strap as it was being pressed in. With all four Italian mags it didn't matter how much you "rock" the release side to side or front to back, it still had to be pressed to the point where the top of the serration adjacent to the border between the smooth and textured part of the grip sank even with the grip before the magazine released. The USA made magazine would sometimes release when that serration was visibly higher but seemingly only if it the release was being pressed rearward. When I find my jeweler's files I think I am going to try to straighten up that edge on the notch in the USA mag and test it again.
The "under cut" on the Italian ones is noticeable on other edges, too, not just the notch for the release. The bluing is much, much better on the Italian ones, too. Makes me kind of sad.
John
