I went this weeekend and there were like 40 people in there.
I didn't get a chance to go today.
I will try to get out on Tuesday and see if it fits in a S&W 59.
I finally got out to Cosners.
He had a P-11 and 5906 in the display case and graciously let me try my mag in them.
The 5906 mag was much longer than the X mag.
The X mag would not even reach up to the magazine catch.
However, the X mag fit right into the P-11 and locked right up with the mag catch.
BUT, it stuck out the bottom of the grip about a 1/4".
So, I went to the KTOG site to find out more.
They had this
[FONT=arial,helvetica]One of the attractive features of the Kel-Tec P11/40 is its ability to use Smith & Wesson M59-series (15-round) and M69-series (12-round) magazines. Many KTOGers are partial to the M69 12-round magazines and use them as spares when they carry. Depending on your body size and type and your mode of carry, it's also possible to use the M69-series magazine (with extension - see below) as your primary magazine in your gun. Most people seem to find the M59-series magazine just too long for use as anything except as a spare or at the range.
...... [/FONT][FONT=arial,helvetica]Both the M59-series and M69-series magazines extend below the grip. Fortunately, Kel-Tec makes magazine extensions that slip over the magazine which create a full grip. The M59-series magazine extension is p/n P11-043. The M69-series magazine extension is p/n P11-044 (NOTE: this part is not listed in the "Pistol Accessories" supplied with your P11/40 or on Kel-Tec CNC's web page). [/FONT]
So, the 59xx mags will work in a Kel Tec but not vice versa, the Kel Tec mags are too short.
I believe this to be a 10 round Smith & Wesson 69xx magazine.
That means there are NO winners.
Reps to:
Geronimoejoe85 for being the first to correctly identify P-11 AND Smith & Wesson in the same post.
target64 for checking his Taurus mags and find some of them were in fact NOT stamped (phone representatives, what can you do?)
Hammer, rbrthenderson, and Mrsmitty for guessing Kel Tec because it fit a P-11.