The high-profile Oct. 23 shootout, just a week before Bolsonaro lost his re-election bid, underscored one of the most daunting challenges facing his leftist rival, Luiz Inacio Lula da Silva.It's something that puts police at risk, and also society," said Bruno Langeani, from the Sou da Paz Institute, who is informally advising Lula's transition team.Although their plans are not settled, they aim to revoke dozens of executive orders Bolsonaro signed to loosen gun laws, which sparked a surge in firearms ownership.Minimizing that vast stock of firearms, many of which are owned by diehard Bolsonaro fans who loathe Lula and dispute his election victory, will be "challenging," said Gabriel Sampaio, a transition team lawyer.Nearly 700,000 Brazilians have taken advantage of Bolsonaro's looser gun laws to register as "hunters, marksmen or collectors," or "CACs," and stockpile weapons."