I bought a Mac-11 / Nine and it only has one mag that was included with the gun, I think it's a Sten mag. It feeds and works perfect.

I see Sten mags for sale from $7.00 to over $20.00 and I want to get some extra mags, what should I buy? Are there different models of sten mags or are they like the AR-15 mags that for the most part will interchange with any AR-15 type rifle?

The only markings on it are "K.C." down near the base and the letter "C" on the front near the top.  Thank you in advance for any help.

hello. yes its a sten mag. there is really only one sten maker to choose from. there arent any better than the others. i have over 100 of them, and had only one mag that was junk. all the others run 100%. go to tactical innovations site, i think they have sten mags for around 2 to 3 dollars.   kirk

www.tacticalinc.com/sten-mags-surplus-p-256.html

MV --
I have a sten mag in excellent condition that I'll give to you next time we cross paths.

-Chris

If it is a sten mag make sure you pick up a surplus sten mag loader. Your hands will thank you for it.