Section 22A. Whoever has sexual intercourse or unnatural sexual intercourse with a child under sixteen, and compels said child to submit by force and against his will or compels said child to submit by threat of bodily injury, shall be punished by imprisonment in the state prison for life or for any term of years; and whoever over the age of eighteen commits a second or subsequent such offense shall be sentenced to the state prison for life or for any term of years, but not less than five years; provided, however, that a prosecution commenced under the provisions of this section shall not be placed on file or continued without a finding.

Whoever commits any offense described in this section while armed with a firearm, rifle, shotgun, machine gun or assault weapon shall be sentenced to the state prison for life or for any term of years, but not less than ten years. Whoever over the age of 18 commits a second or subsequent such offense shall be sentenced to the state prison for life or for any term of years, but not less than 20 years.