Something something assault rifle.
edit: fixed missing crediting for the angled foregrip.
something something junk gun that looks a whole lot like a glue gun.
something something 50 BMG automatic rifle.
"Why though"
Power armor.
The rifle is chambered in 50 BMG and it comes in only automatic and single shot, instead of using a small paddle (I really didin't have enough space for it) I simply attached a second trigger onto the rifle that worked as a magazine release, which worked more or less like the AR-15 magazine release (where you can drop the magazine with your right hand and grab another with your left one). As you could see on the handguard there is that block on the rear of it, that being a universal attachment tool that works on all my attachments, those being handguard w/ flashlight, Underbarrel Automatic rifle and the double barrel grenade launcher, working under two fire modes (safe/fire or on/off for the flashlight)
It was honestly fun to make, even though the concept is pretty far fetched.