Yes, I have two barrels from them....the 506's are GTG. I have an 18" fluted S.S. Green Mountain Barrel and a Ruger factory barrel on other rifles and they all shoot equally well. I am not a competition shooter but I can hit quarters at 25 yds, half dollars at 50 yds and dollars at 100 yds with any of them.
Their site might appear to be a little sketchy but delivery was quick and packaging was fine.
roy d...enjoy!