Hey I was able to get my hands on a ACM M500 gas shotgun. The pump arm has already been replaced with a reinforced allunium part and the stock and handguard have new black polymer parts. The last thing I wanted to add was a barrel shroud but I kinda hit a brick wall in where to buy and how to install. Heres the gun in question if you don't know. http://www.evike.com/product_info.php?products_id=29939 If you look at the video review you'll see the shroud I'm looking to add. Any advice would be appreciated.