Brand? Mag capacity?
Sorry I am not sure on either of those... Haven't been airsofting long enough to know all the little details. Mag capacity is well above 13 because that is the most I have ever put into the magazine.
Since you're new i'm going to assume it was 150 new? In that case its OEM is KJW. The mag should hold around 28 rounds
I never paid for it... It was given to me as a training weapon, but you seem to know what you are talking about so I will take it as that. I checked the magazine capacity and I got it told hold 27 LOL