An adapter for a flooring nail gun is provided with a muzzle member including at least one set of two inclined cavities; a moveable member including at least one set of two inclined protrusions at an end, the inclined protrusions being disposed in the inclined cavities; and a quick releasing device disposed on the inclined protrusions. The quick releasing device includes a pressing member, a spring member, and a lever, and wherein the pressing member and the muzzle member are joined, the lever and the pressing member are pivotably secured together, and the spring member has one end anchored at the pressing member and the other end pivotably secured to the lever. The moveable member can be opened for troubleshooting in case of malfunction.
