A usually reserved Sen. Jacky Rosen — who seeks re-election this year as a Nevada Democrat — laid into Sen. J.D. Vance (R-OH) on Monday over his remarks that Democratic-led bump stock ban legislation is likely aimed at a “PR problem, not something that’s going to meaningfully reduce gun violence in this country.” After the Supreme Court struck down a ban on the rapid-fire gun attachment — used to slaughter 58 people in Las Vegas in 2017 — Vance talked with reporters Monday about Senate Democrats’ effort to ban them. “I think that we have to ask ourselves: What is the real gun violence problem …