Yes I did call Ruger to verify what ammo they frown upon. I made that phone call this afternoon around 3:45 p.m. As I stated they did indeed mention Sellier&Bellot as one to stay away from. I would imagine it would have to with how dirty it is. Wolf was also frowned upon because of it's dirtiness. The reason I had made this call was because I had heard they frowned on Wolf was because it was loaded HOT. Needless to say, after they answered my question I had about Wolf, I asked if there were any others. Thus they answered: Sellier&Bellot, 3D, American Ammunition in .40cal and .45acp(due to weak cases).