I recently purchased a Tac Four, same as a P13, and am looking for some 13 rounds mags for it.  Wondering what brand everybody had the best luck with.  I looked at Mec Gar but can only find 10 rounds and have seen some CDNN but have never heard of them?  Any help is appreciated.

I've orderd some factory 10 rounders from 44mag.com.  Don't buy ProMag, no matter how appealing their low price is.  The 13rd mags will cost you $40 or so.  Factory 10rd mags should cost you around $20 or so.  Check the EE and I hate to say it, Ebay, and gunbroker.com  Be sure to ask the seller if they are factory mags or aftermarkets.  I know waiting for a good deal can be aggravating.  Just put aside some cash and wait for it to come along.  Took me 4 months to come across a deal on a Safariland 3004 drop leg holster for my Tac Four.  Picked it up for $20.

Had one seller on Ebay advertising factory 10rounders for the P13 at a super low price (if price is low, probably ProMag).  Asked seller if these were genuine factory or aftermarkets.  Never replied to my question (another hint they are ProMags).

Enjoy your Tac Four.  I got one also in stainless.  It's a tack driver.  Make consistent 50 yard hits on steel plate with it using Wolf ammo.