not sure the exact series, I got it in a trade the guy said it was a WOC, I replaced all the internals with steel ones and got a new rail (it doesn't fit perfectly but I still have the original as seen in the second picture, the new rail fits tight as long as you have something holding the two rails together hence the holographic sight) it does need a new bolt right now and I would suggest getting a steel one, I'm not really looking for trades, I know one of the mags doesn't work but the other 3 should if I'm correct (2 do for sure I'm not positive on the third but if you are interested I'm more than happy to test them out) price is negotiable located in Charlotte