Thanks, Wayne. I looked at most all of those links tonight. One thing I remember Bill Ricca saying was that no USGI mag would (not?) have that one hole in the back - not sure if he was talking about the drain hole at the bottom or the hole you can see in the back of the follower. He must have been referring to the follower - Also, I wasn't aware of that "wrinkle" since I've never had mine apart. I wouldn't say that the AYP is especially "robust" - maybe even looks a little cheaper than an SEY split-back. I compared the weight to an SEY and the AYP is about 3 grams lighter. - Bob