This pre-War model was originally used by construction crews for demolition. Fitted with a rocket booster at the head, the sledgehammer would behave like a normal tool until it reached a certain acceleration point, when the booster would activate and deliver a tremendously powerful impact, easily crushing concrete. Of course, its use required carefully selecting the target area and trajectory, as while the operator was protected from the recoil by the shock dampener in the handle, everyone around them was vulnerable. Of course, it certainly didn't take much imagination to find alternative uses for the existing units after societal collapse.
↑The Art of Fallout 4 p.234: "Chapter 5 WEAPONS ONE OF THE CORE Fallout experiences is surviving in the Wasteland through combat, so we set out to give the player a system that allows modification and customization of any weapon in the game. Every gun was designed with modularity in mind. Classic guns, like the plasma and laser rifles, were broken up into interchangeable components. New guns, such as the pipe set, were designed from the ground up to work with this system and provide as much variety and flexibility as possible. The pipe gun set is the most basic of the ballistic weapons, crudely crafted from various bits of found bolts, metal, and wood. These guns look just as likely to kill the shooter as the target, but they are plentiful in the Wasteland and a favorite of raiders. We used this early set to figure out how we wanted to break a gun down to the basic elements that all guns would share, in order to maximize interchangeability. This drove the structure of the crafting interface, with standardized slots for receiver, barrel, muzzle attachments, grip, and scope. The root identity of any gun is determined by the receiver; everything else can be swapped. This allows the player to go as far as transforming a short-range pistol into a sniper rifle. Luckily, given the improvised nature of most things in the game's world, weird or unusual gun combinations still look appropriate and fit into the setting. Some of our guns are based on realistic interpretations of well-known, real-life prewar weapons, and therefore their range of customization options is slightly limited. But even in these instances you can substantially change the gun's appearance to achieve some really interesting builds. The base 10 mm, for instance, is a different design from the version in Fallout 3. But with the proper mods, you can transform it into something very similar. It's not all about the guns, of course. The melee selection was expanded as well, with a eye toward entertaining builds designed to deliver massive (and painful) physical damage. Some of these weapons were initially intended for purposes other than inflicting harm. The power first and super sledge are prewar hardware originally used by construction crews for demolition. But it certainly didn't take much imagination to find alternative uses for them."