Sen. Dianne Feinstein (D-CA) came away from a Monday meeting with Senate Majority Leader Harry Reid (D-NV) "frustrated" that her proposed assault weapons ban left out of her party's gun safety bill.

According to Politico, Feinstein's proposal, which she offered in the wake of the Newtown Elementary school shootings in December 2012, could still be offered as an amendment to the party's bill, which substantially decreases its chances of passing.

"I would like to [see the bill moved], but the leader has decided not to do it," Feinstein said, adding that reporters should ask Reid why the ban, which covered 157 kinds of high-capacity firearms, was dropped.

Mother Jones reported that both Feinstein's ban and a proposal for universal background checks for prospective gun owners were approved by the Senate Judiciary Committee in votes that broke down along party lines.

Instead, the Democrats' proposal, which is expected to be introduced in April, may focus on "straw purchases," in which buyers purchase guns for people legally barred from doing so, with additional features dedicated to increasing school safety.