The webmaster of G&P Industrial Co. Limited has sent in the latest news, and one I personally welcome since I've been thinking of putting a custom SR15 together as a project. One release is the SR15 URX E3 Metal Body (B Type), the and XM177E1 Steel Outer Barrel. Better check with your favourite retailer if they already have this in stock as G&P metal bodies always run out of stock (I've been looking for the SR25 CNC model which comes complete with a gearbox. It's available, but I'm still holding out for a better price).  All these items are compatible with Marui models.

"Hello, we have release new products!

GP702B  SR15 URX E3 Metal Body (B Type)

GP760    XM177E1 Steel Outer Barrel

Best Regards,
G&P Industrial Co., Ltd"