PT111 Mill. Pro Mag. Question

[hysteriapb]

So today i purchased a PT111 9mm used from a private collector at a gun show. It is in very good condition. My problem is that the mag it came with seems to be the wrong one...     It fits in the mag well fine but it wont lock in place and it doesnt activate the slide lock like it should, thus the belief it is the wrong one. I was looking for new mags online and came across a note posted on one site that said that Mill. Pro's and regular Mill. use different mags. So I'm wondering if this could be a regular Millenium mag... Any help would be great.

Edit: Update - the kindly folks at Gander Mtn. said that it does indeed belong to the non-Pro version.

[sundogg1911]

The regulat PT111 is a 10 rounder, the Pro is a 12. I have an Older PT111 It's a great carry pistol. It has a really long trigger pull (Like most DAO's) but that's about the only thing I don't like about it.  Out of my 20 some pistols and revolvers, it's probably the one that I carry the most.

[hysteriapb]

ya I really love the way it handles and feels. I'm just not real thrilled about not bein able to shoot it yet... 
edit again: you don't want another mag for that fine piece do ya? i have no use for it. I'm just gonna sell it i guess.