Its not the key lock....
Its the internal latching bars and mechanism.. pull the thing off, disassemble it, scrub it well with scotchbrite pads, and grease every nternal latch part with lithium grease...
Ive'm currently looking for a local metal plater thru my vast network of engineering contacts, to offer up an affordable option for some plating that is better than that damned zinc chromate conversion, and jnplated aluminum bars.. I'll post up when I get a good source for plating all the parts that matter.. untill then, scrub, and grease them..