It is plastic and that seems like a bad idea considering it isn't a solid part. Also considering how it is built and adjusts I don't think it will accept a battery very easily if at all.
I realize the Angry Gun adapter I linked isn't the most affordable but that part is really the foundation of the conversion you are doing. Not to mention it is probably the best quality adapter you can buy, and you won't have to worry about international shipping.
Durate et vosmet rebus servate secundis.