WASHINGTON (AP) — The Senate is ready to renew an expiring ban on plastic firearms, the kind that can pass through metal detectors and X-ray machines unnoticed.

But Monday's vote will be bittersweet for supporters of gun control.

It comes days before the anniversary of the deadly mass shooting at Sandy Hook Elementary School in Newtown, Conn., where 20 children and six educators were killed Dec. 14.

Congress has approved no new federal curbs on firearms since then — although President Barack Obama made it one of his top domestic priorities.

Monday's vote is to extend the prohibition on undetectable plastic guns for another decade. That ban would expire Tuesday.

But gun control advocates seem sure to lose an effort to impose tougher restrictions.

Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.