(concurring, with whom Spina and Cordy, JJ., join). I agree with the court’s conclusions and reasoning, but write separately to diminish the risk that the peculiar manner in which the Commonwealth chose to draft the armed robbery indictment in this case may invite confusion regarding our holding.
Under G. L. c. 265, § 17, “[w]hoever, being armed with a dangerous weapon, assaults another and robs, steals or takes from his person money or other property which may be the subject of *268larceny shall be punished by imprisonment in the state prison for life or for any term of years.” Under § 17, where a defendant commits armed robbery “while masked” or “while armed with a firearm,” the defendant “shall” be sentenced to no less than five years in prison for a first offense.
Had the Commonwealth drawn its indictment to allege the crime of armed robbery with a dangerous weapon, the defendant would properly have been found guilty of armed robbery because the BB gun in this case was a dangerous weapon, which under our case law includes a weapon that appears to be a firearm, even if not actually a firearm. See Commonwealth v. Powell, 433 Mass. 399, 400-401, 404 (2001) (affirming conviction for armed robbery with dangerous weapon where defendant used fake shotgun and it was reasonable for victim to believe that weapon was real). If the Commonwealth had sought a mandatory minimum sentence, it could also have alleged two separate sentence enhancements in the indictment, one alleging that the defendant had committed the armed robbery while masked and the other alleging that he was armed with a firearm. Had it done so, the Commonwealth could have obtained the sentence enhancement arising from the commission of the armed robbery while masked. For the reasons given by the court, the Commonwealth was not entitled to the sentence enhancement arising from the commission of the armed robbery with a firearm, because a BB gun is not a firearm.
The evidence in support of the armed robbery indictment in this case is insufficient only because the Commonwealth alleged that the defendant committed the robbery “while being armed with a handgun,” rather than while being armed with a dangerous weapon. As a result of this charging decision, the armed robbery indictment may stand only if the defendant was armed with a handgun, which he was not. It is for this reason that we affirm only the conviction of the lesser included offense of unarmed robbery. In short, the Commonwealth in this case unnecessarily chose to make conviction of armed robbery rest on the defendant being armed with a firearm, when it need only have rested on his being armed with a dangerous weapon.