I have a SR9 that I am converting to a quasi MSG/PSG rifle. I was wondering if anyone has used MAGPUL stocks with HK rifles? Specifically the MAGPUL PRS G3 Preproduction! Secondly, has anyone used the HARRIS Bipod adapter for mounting a harris bipod to HK91 wide forearms? I am aware that I will have to drill a hole in the forearm to get the sling mount adapter to stick out of the base of the forearm. Your thoughts!!!