Get your own airsoft----- no, airHARD---gun and face off. The grenades and mortars will be useful. Grab all the weapons you can possibly hold, intimidating him. Put the rest behind him, each in the hands of a loyal lawn gnome. Lie and say that you have your OTHER communism-torn lawn gnome slaves inside loading a five-pound rampart cannon. If he does not surrender the gnomes he stole, it will fire. And so will you with all your cool weapons. Try that.
Children, this is what happens to hockey players, druggies, and Hillary Clinton.