Massachusetts gun laws use the term “large capacity” to describe certain firearms and magazines. That label affects how police charge a case and how courts punish it. If you own or handle a firearm, it helps to understand what the law means by large capacity.
How Massachusetts defines large capacity firearms
Massachusetts law separates large capacity feeding devices from large capacity weapons. A large capacity feeding device is a fixed or detachable magazine or similar device capable of accepting more than 10 rounds of ammunition or more than 5 shotgun shells. A large capacity weapon is any firearm, rifle or shotgun that is either equipped with a fixed or capable of accepting more than 10 rounds of ammunition or more than 5 shotgun shells; or is an assault weapon.
Why magazines and feeding devices matter
Magazines often determine whether a firearm counts as large capacity. A firearm may qualify even if the magazine is not inserted, as long as the person also has a qualifying feeding device nearby or under control. Some magazines receive permanent changes to limit how many rounds they can hold, and when those changes truly block the magazine from exceeding the legal limit, the law does not treat it as large capacity.
Why September 13, 1994 matters
Massachusetts law refers to September 13, 1994, because it links some rules to older federal gun laws in effect on that date. State law also allows limited possession of certain large capacity feeding devices that were lawfully possessed on that date, subject to strict rules. Because of this, cases may focus on proof of “grandfathered” lawful possession rather than just when a magazine was made.
How large capacity charges raise penalties
Large capacity charges bring tougher punishment than standard firearm offenses. These charges can trigger mandatory minimum sentences and reduce a judge’s flexibility at sentencing. The label may also affect bail decisions and how prosecutors approach the case.
How the definition affects real cases
In real cases, large capacity charges often depend on technical details. Police document firearm models, magazines, and compatibility, and disagreements often arise over whether the law truly applies. Understanding the definition helps explain why small details can make a big difference.