you may have a minor problem. on my pt1911 i replaced the factory slide stop with an extended. my mags wouldnt drop with the new part. it turns out that the "stub" that the mag follower pushes up to lock the slide was too short. that was the cause of the slide not locking. and when the slide did lock the follower would "run over" the "stub" and that wouldn't allow the mags to drop. when i pulled the mag out it in turn pulled the slide stop down and the slide would fall. it may be as simple a fix as a new slide stop for you. just a place to start and my .02 worth.