Looks like kg333 covered it well; that's how I understand the issue, anyway.
Originally Posted by kg333
I have some original Glock 17 magazines that are 18-20 years old and still perking right along. I wouldn't choose them over the most current versions for defensive uses, as I think some useful enhancements have been made over the years, but they seem to still be working as well as they ever did.
"Placement is power" -- seen in an article by Stephen A. Camp
(RIP, Mr. Camp; you will be remembered, and missed)