I explained to my gun store: " If it's used, then there is no harm in me shooting it on your range right? And I can field strip it to check out it's guts right? Used is still used, it's not going to lose value just becuase I tested it out."
Trading a pefectly good Warrior for a broken MM is not a good idea. Try it out first. If they can't, or don't have a range and won't let you borrow it with your Warrior as collateral, pass.
And the golden rule: "Never sell a good 1911, only an unreliable one."