I won't say all are, but the vast majority of those "co-sponsors" on those, HPA, and anything similar are only looking to get kudos from the NRA's grading system yet have zero intention of actually pushing for the bill's passage. Last month before the turnover but post election, they "passed" it knowing full well it was dead in the water in the Senate, so they could grandstand and claim to have voted for the bill, get brownie points on those who mildly look up their voting record come election cycle, but never do anything like arm a populace as the Founders intended.
Like AJ said, the GOP had two years of full control and did nothing. They could have pushed the votes prior to the midterms, let the dems actually put on record who and what they cared about that could have actually caused some sway to the conservative side by giving a verifiable stand on rights infringement vs. freedom. But instead they knew that wasn't what they wanted in the first place, because they're power hungry and are threatened by a strong citizenry just as much as the dems are.
Fuck them and their coveted seats, the sooner the government swings full liberal, the sooner we can get on with fixing this bullshit.