I have been looking into that very subject. I have an HK21 clubfoot buttstock with heavy buffer. I was thinking of researching and possibly doing the modification and installing on this rifle.Good looking rifle, thanks for showing the build. If only surplus ammo was cheap and plentiful for them. Do you have any experience with the heavy duty buffers, like the ones that RTG sells? I don't mind recoil, but making faster follow up shots would be fun.