From the Super Mario Wiki, the Mario encyclopedia
A Kritter wielding a Klap-Blaster

Klap-Blasters (originally referred to as Klaptrap Weapons) are wooden projectile weapons commonly used by Kritters on the Donkey Kong Country animated series.

Instead of regular ammunition, Klap-Blasters shoot a barrage of Klaptraps which can chew through almost anything. However, Klap-Blasters are occasionally seen to shoot explosive projectiles.

Oddly, it is never explained how a Klap-Blaster can hold so many Klaptraps when the weapon's ammunition holder is actually extremely small.