The Gun — Philip K. Dick

In The Gun, a group of space explorers are shot down above a deserted planet. While some of the crew work on repairing the ship, the remainder set out to investigate the planet. Otherwise unpopulated, they discover the huge gun that shot them down sitting atop a trove of cultural artifacts from a bygone civilization. What harm could come of dismantling the gun and taking a few of the artifacts home with them?