Despite their overwhelming popularity, assault weapons like the rifle used by the Sandy Hook Elementary killer are very rarely used in crimes, according to a comprehensive Congressional Research Service report on guns and gun control legislation.

Citing a survey of 203,300 state and federal prisoners who were armed during the crime for which they were incarcerated, “fewer than 1 in 50, or less than 2 percent, used, carried, or possessed a semiautomatic assault weapon,” said the report.