Hi there,
This is my first post, because I actually feel I have a legitimate reply. Call Beven Grams, period. He built 8 STI .40 mags for me and they are perfect. Granted he is a busy man, but when you do reach him, he will gladly talk you through anything and spend time with you. He supports the sport, builds great products, and helps his clients. Top-notch guy, just give him a call at 949/548-3745. Leave a message, and be patient, he will respond.