When I was in the infantry, I used to absolutely love shooting the M-79 grenade launcher (looked a single shot shotgun on steroids and loaded like one - we called it 'The Blooper') which also shot the 40 mm grenade.
When we were planning on firing the "chunker" on our Huey gunship we would remove all the 'eyebrow' light bulbs on our instrument panels or when we fired, the shaking would pop out onto the deck. It did shake the ship a bit.
The M79 is long gone. IIRC, the SEALs were the last ones to use it. It was replaced by the M203, which mounts under the M16/M4. The M203 is, in turn, being replaced by the M320A1, whcih can be mounted underneath a rifle, or utilized in a stand-alone mode.