If I try to carry a five inch 1911, I also find the barrel bumping a bit when I sit down. As WVsig said, the Duty Treatment is a pretty good metal treatment.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.