I remove mine each time, and clean it. If nothing else, you need to get whatever fouling worked its way down between the barrel and pan. I spray mine down with CLP, scrub it with a toothbrush and Q-Tips, and let it drain on a paper towel. No excuse for a rusty lock.
To take the lock out, unscrew the bolts about 3/4 of the way, and use the heads to press the lock free. Then unscrew the rest of the way.
God Bless, Marc