Something i think about is how the concept art of the game admits the pipe guns aren't meant to look like real guns, just "gun shaped". The devs did it intently :
NPC gun animations fucked up - Fallout 4 Technical Support - LoversLab
Fixing Fallout 4's Pipe Weapons - Mod Bundle - YouTube
Nina's Proper Pipe Guns Replacer at Fallout 4 Nexus - Mods and community
Pipe gun (Fallout 4) | Fallout Wiki | Fandom
Fallout 4 Rusty Revolver Animations - YouTube
Steam Community :: Guide :: Atmospheric and Lore-Friendly Modpack
Fallout 4 Top 10 Animation Mods - YouTube
Pipe gun (Fallout 76) | Fallout Wiki | Fandom
Pipe rifle (Fallout 2) by MG-Croft on DeviantArt
Pipe gun (Fallout 76) | Fallout Wiki | Fandom
I grew tired of the vanilla rusty pipe guns ... so I retextured them all (including revolver and syringer). XBox and PC Links in comments [Fo4] : r/FalloutMods
Monthly Modder: The6thMessenger
How plausable are the pipe weapons in Fallout 4 IRL? - Quora
ArtStation - Pipe Gun Retexture - Fallout 4
Fallout 4 Weapons | Tesgeneral
Pipe RIfle | Fallout 4 Wiki
PIPE WEAPONS OVERHAUL - Fallout 4 Mod Review - YouTube
Pipe Assault Rifle at Fallout 4 Nexus - Mods and community
Scrap metal and makeshift welds - A Pipe Gun Retexture at Fallout 4 Nexus - Mods and community
Pipe rifle Fallout 4 - Download Free 3D model by olofunot (@olofunot) [1139cc9]
Steam Workshop::Project Fallout: Pipe Rifle
Fallout 4 Pipe Pistol - 3D model by jayheath91 (@jayheath91) [201ed43]
Anderson Junior - Pipe Rifle - Fallout 4 Weapon
Fallout 4 Weapons | Tesgeneral
Pipe Assault Rifle at Fallout 4 Nexus - Mods and community