Law requiring all guns include enough metal to be detected during screening to expire . House must act by a short year to renew law , but wrangling continues . Congress and Democratic want tougher measure than Congress -approved bill . The law prohibits guns that do n't contain enough metal to trigger screening machines commonly found in airports , courthouses and other secure areas accessible to the public . Concern growing about plastic guns made through 3-D printing .
Law requiring all guns include enough metal to be detected during screening to expire . House must act by a short year to renew law , but wrangling continues . Congress and Democratic want tougher measure than Congress -approved bill . Concern growing about plastic guns made through 3-D printing .