Gillibrand is hoping to ward off a primary challenge from McCarthy, a gun control activist, by co-sponsoring a bill to close the "gun show loophole" and tacking to the left on gun issues in general.
But now comes this:
But McCarthy said that next week she plans to introduce an assault weapons ban - legislation that is anathema to the NRA and that could pose a problem for Gillibrand.
"I think the assault weapons bill will be a test," McCarthy said Wednesday in an interview.
Gillibrand had no comment Wednesday on legislation that hasn't been introduced, said her spokesman Matt Canter.
While in the House, Gillibrand earned the endorsement of the NRA, a rarity among Democrats. McCarthy says she still intends to launch a primary challenge, but nevertheless appreciates Gillibrand's policy shifts.
"She actually has been signing things we have been sending over to her," McCarthy said. "And I am very happy about it. I just want to make sure she stays there."