Need to shoot down mutants the old fashion way with cannon balls? Well, you can with the Broadsider cannon gun in Fallout 4. Considered as a rare weapon, you will be able to obtain this gun from Captain Ironsides during the Last Voyage of the U.S.S Constitution quest.
When normal bullets or lasers don’t get the job done, turning to a cannon will always solve any problem, especially in the wasteland. To wield this dangerous cannon with big ballistics, you will need to talk to a Mr. Handy service droid named Lookout, who’s outside of the U.S.S Constitution ship. Lookout will give you the quest Last Voyage of the U.S.S Constitution.
After talking to the bot, you will need to talk to Ironsides, not to get confused with Doctor Who, which will grant you a side-quest that will take you on various missions. During one of the missions that it sends you on, you will have to make a decision to join the scavengers or stick with Ironsides.
In this case, if you want the Broadsider, you will have to stick with Ironsides and skip the scavengers. After completing that part and killing the scavengers, you will be granted the Broadsider. You can watch a video that TwoDynamic posted, showing how to get the rare cannon gun in Fallout 4.
Although this gun is quite powerful, its considerable weight, low range, lack of being able to iron-sight, low ammo capacity, and its sorta rare ammunition makes it not so great. Not to say that you shouldn’t get it, but it does have its drawbacks.
For those looking to get more cannon ammo for the Broadsider, you will be able to get ammo from certain shops, and during the quests Old Guns in the castle, and Fort Strong in the back of the fort. While participating in those quests, you will be able to get more than 10 cannon balls. Hopefully this helps out those wasteland scavengers in Fallout 4 looking to find some rare weapons to make the adventures a little more unique.