So I bought 6 new STI Magazines from Brownells for my 9mm Eagle. Two of them insert perfectly and lock into the mag catch with ease. Of the remaining 4, two of them just won't seat and the other two will seat, but require an amount of force that it completely unacceptable for competition use. I called STI and their voicemail inbox is full, so I sent an email with no reply yet.
My thought is that the notch on the magazine needs to be opened up at the top, but before I go filing on nearly $300 of gear I'd like to hear some thoughts on the matter. I have tried these on my Edge too and got the same results.