I did check, and You Only Live Twice had a few of them.

This .49 caliber rocket gun only weighs in at .88 lbs (.4 kgs). This is because they were able to make it out of a zinc alloy. Unlike most guns rocket guns experience much less pressure so they don’t require steel barrels.

It’s failings mirrored that of the Volcanic Pistol low muzzle velocity and poor accuracy (~17 moa).