Have you checked Gun Broker?

How about the EE here?

I tried at one time to have an aftermarket mag made. Somehow the Bafretts found out and told the 2 manufacturers about it. Someone at Barrett told the 2 compa ies I talked that the mag was proprietary and was patented. That killed the discussion right then.
I told both companies that it was a box magazine and nothing special about it. No patent at all. No one would talk to me after that.

I don't know of anyone else that makes an aftermarket mag. The Serbu semi auto uses the Barrett mag. Maybe contact Mark and see what he uses as supply.

@Ben

I'm trying like he'll to find a decent priced m82 or serbu bfg50a. When I got on the serbu list, I was told 3 years. I won't wait that long.