I recently picked up a slightly used G21 at a price i couldn't pass up. My G30 was getting lonely, all by her lonesome. This G21 is a sweet shooter. Ran 100 plus rounds through with no hiccups. Almost like it better than the G30. Guess i can't complain with two nearly flawless pistols. Now for the $10k question. It came with the factory adjustables installed and I would like to remove them in favor of the Warren Tactical set that I installed on my G30. Do the factory adjustables simply drift out as the fixed, or are they set screwed in place??