I have been wanting the 9mm conversion barrel for my .40 service since I purchased my gun...last week at the range I met an individual who customizes 1911's and was told that the conversion barrel "may well be drop-in, but that you'll destroy your extractor ultimately" supposedly because of "too much play" at the breach face. Is this true? Not fully understanding his explanation I would like further education on the topic, especially since I REALLY wanted one of the conversion barrels! :?