It is kinda bizarre that ANYONE would think that owning .50 caliber ammunition, many guns and a Hand Grenade is supposed to be a legal thing.
For anyone who has been around the Armed Forces, such weaponry is known as Anti-Personnel Weapons. In short it is not for John Q. Hunter to trod through the woods to kill Bambi.
These things kill people. Also in a city like Fitchburg where guns are rampant, constantly in the wrong hands, and with all the shootings over the past 2 years in the city (Something that the folks in Massachusetts, and the German from Corning, New York wouldn't know about, nor would they know where Fitchburg is!) it is the last thing needed in Central Massachusetts.
All you need is one drug dealer to break into that apartment, and you have a drug dealer with a hand grenade, and ammunition that could peirce the armor of a person, vehicle etc.
.50 caliber ammunition brought many a Luftwaffe Pilot an early death (something that our HerrBGone from Corning, NY should know about..), and such could cause many problems.
Also, having lived in Maine almost as long as I have lived in Fitchburg, I have read newspaper reports of minors being killed with guns in their homes.
But what is more troubling that anyone would rationalize the need to have/own a Hand Grenade.
The Fitchburg Police should be credited for this, as such weapons need not be a part of the City of Fitchburg.