I could probably hide a curved 20rd mag inside of a M14-sized housing, while still keeping straight mag appearance, if it meant a lot to someone. Dunno how it'd look. I'll have to think about it.That straight mag looks great. You guys shooting 5.56mm can get away with that, but the 7.62 x 39 I shoot needs some curve.
Since you are going for the M1A look, now you'll need to drill a hole in your safety tab.