MGL Chapter 140, Section 121A:
Ballistics Identification

Section 121A of MGL Chapter 140^[1] allows a sworn certificate from a qualified ballistics expert to serve as prima facie evidence identifying whether an item falls within specified statutory categories. In a criminal trial, however, a testimonial certificate cannot substitute for live testimony over the defendant's confrontation objection under Melendez-Diaz v. Massachusetts and the cases applying it.

Key Requirements

The certificate has prima facie effect only when issued by a ballistics expert of the Massachusetts Department of State Police or the City of Boston. The expert must have previously qualified as an expert in a court proceeding. The certificate must be both signed and sworn, and the item must have been furnished to the expert by a police officer.

The certificate is prima facie evidence of the expert's findings. Defendants retain the right to challenge findings, cross-examine the expert, or call their own expert.

Penalties

Section 121A does not prescribe any penalties of its own. It is purely an evidentiary rule. Penalties flow from the underlying substantive offense, such as unlawful possession under MGL Chapter 269, Section 10^[2].

Chapter 135 Impact

Section 121A was not amended by Chapter 135 of the Acts of 2024^[3] and is not subject to the November 2026 referendum. However, because Chapter 135 significantly expanded the definition of "firearm" in Section 121 to encompass rifles, shotguns, frames, receivers, and weapons "designed to or may readily be converted to expel a shot or bullet," the scope of what a ballistics expert would certify under this section is indirectly broader.

Related Provisions

Section 121 provides the underlying definitions that expert certificates authenticate. MGL Chapter 269, Section 10 is the primary carrying offense where such certificates are used as evidence. Section 131Q addresses firearms evidence in criminal cases.