A suppressor for a firearm includes a casing that defines an axis, and a baffle is in the casing. The baffle has upstream and downstream surfaces and a frustoconical surface between the upstream and downstream surfaces. The baffle defines a fluid pathway through the upstream, downstream, and frustoconical surfaces along the axis. An annular chamber is located between the frustoconical surface and the casing. A first contoured wall extends upstream a first height from the upstream surface, and the first contoured wall defines a perimeter around a first damping well in the upstream surface. A second contoured wall extends upstream a second height from the upstream surface, and the second contoured wall defines a perimeter around a second damping well in the upstream surface. The first height of the first contoured wall is larger than the second height of the second contoured wall.