when I had mine I could get only the tens twenties and thirties. You can use pmags DPMS metal mags, and what other kind seems like it was either M1 or M14 but the other two or more widely available and cheaper. I don't think anybody makes a 15 rounder.
Does anyone know of a 15-round magazine that will fit the Mossberg 308 MVP LC?
If you could find a metal 20 rounder, you could have it pinned at 15. Problem is getting a 20 rounder shipped to you. Good Luck!!
Sir, did you see my link to Checkmate Industries in post #5?
They are top notch quality, the present CAGE manufacturer for USGI M14 magazines used by our military.