Shaun Leonardo is tired of people talking about guns. So, at the Guggenheim, he’s trying something different: “Mr. Leonardo, a former wrestler and college football player (who still has the physique to prove it) announced in advance that the performance would be inspired by one of the roughest sporting traditions to endure in the 21st century, the Italian Renaissance-era game of calcio storico. (Imagine a mix of rugby, soccer, martial arts, wrestling and fist-fighting rolled into one nearly lawless clash.)”