Here is a good piece by John L . Marshall . He likes to be called Mr. Marshall.
At the risk of some using this info to destroy their guns, I think it is good info for the responsible members here at the fire.
http://www.sightm1911.com/?s=reliability Some good points there, but where he said, "don't grind on the barrel ramp too much" I had to cringe.
Buy Kuhnhausen's book, and he'll tell you exactly much you can grind it