I got the replacement holster today and I'm having the exact same issue. The gun slides in perfectly but the retention mechanism doesn't lock as intended. It can be forced to work but I'm not going to trust a holster that I have to "make" work especially when IMI and the company I ordered through stated it would work with my firearm.
It really is a shame because they have a ton of attachments for these holsters that make them compatible on just about every type of webbing/platform.
I can say that the customer service was top notch and I did receive a full refund. They even asked for a detailed description of the problem and a picture of my gun to see if the factory was screwing up.
Figured I'd let others know in case you were looking at this holster. Maybe the others work?
*meant to put this in the holster review resource but screwed up*
![Image](http://31.media.tumblr.com/2c40a9a60557137850c68e676dbd8cad/tumblr_mx7axycdsw1r4d968o1_500.jpg)