Despite a deep desire from anti-gun Senate Democrats to greatly expand the Undetectable Firearms Act (18 U.S.C. § 922(p)) to include exploding death shard machines 3D printed handguns and polymer magazines, it appears that Congress will follow the House plan, which is a simple renewal of the existing ban.

US Congress is heading towards renewing a prohibition against firearms that can evade metal detectors and x-ray machines. However, with 3D printers increasingly able to produce plastic weapons many Democrats, gun control advocates and law enforcement officials say the restrictions must be tightened.

The Republican-led House of Representatives is expected to approve a 10-year extension of the 25-year-old ban on Tuesday. Reluctant to oppose renewal and anger allies, the Democrats are expected to back it strongly, despite their preference to also require permanent metal components that would make plastic firearms more detectable.

“We can’t let a minute or hour or day go by without having a renewal [of the ban],” said Brian Malte, a director of the Brady Campaign to Prevent Gun Violence. The group’s strong concerns about the availability of plastic guns were “no reason to hold up renewal”, he said.

The Democratic-run Senate returns from a two-week Thanksgiving holiday break next Monday, the day before the ban expires. Democratic Senator Chuck Schumer said he would seek fast approval of a measure renewing the ban and tightening the restrictions.

But many believe the Senate will then accept the House bill, thanks to the imminent deadline and the eagerness of Democratic senators seeking re-election next year in Republican-leaning states to avoid difficult votes in a fresh battle over gun control.

Importantly, the National Rifle Association is not making an issue of the House’s renewal. Lawmakers will view this non-opposition as tacit approval.

Anti-gun Senate Democrats want to push a much more restrictive bill that would ban not just 3-D printing, but also polymer aftermarket magazines in apparently punitive legislation that seems aimed almost directly at polymer accessory giant Magpul. This bill would trigger a war that vulnerable swing state Senators and Democratic Senate leadership would rather avoid as we head in an election year.

Look for the House bill to pass.