Meanings of dropping the butt in English

"There!" said Le Cabuc, dropping the butt end of his gun to the pavement.

"Holy Heaven!" exclaimed Guert, dropping the butt of his rifle on the ground; "we are too late!"

"The skulking reptyle brought it on himself," muttered Pathfinder sternly, as, dropping the butt of his rifle, he carefully commenced reloading it.

"Now, Archie," said Frank, dropping the butt of his gun to the ground, "there's a chance for you to retrieve your lost reputation."

"Run, bub, and pick him up," said Plutarch, dropping the butt of the rifle and resting it carelessly on the toe of his shoe.