Frank is fucking based, only he is confident and alpha enough to show up to this pathetic omega's house knowing full well that he was armed and had expressed intention to kill him. Even under these circumstances, where it is very likely that Boogie could have legally shot and killed Frank, he was too much of a pussy to do it after his myriad of threats and Frank knew this.
This was absolutely going to be the outcome, anybody who knows Frank's work knew this would be the case. He doesn't back down from anything even if it's completely retarded and would get him into serious trouble. Boogie threatening to kill him only made him want to go to his house and test it, he wasn't going to let some fat fuck on the internet think he came out on top. Not only that, but he laughed at Boogie's flaccid warning shot before eventually leaving. Was showing up at his door the right thing to do? Hell no; it was fucking retarded, possibly illegal and playing with his own life. But 'retarded' and 'possibly illegal' are Frank's MO.