Not included with the mod but the pipe weapon scope shown in the pics above is using Gmoi6 'Scrap metal and makeshift welds - A Pipe Gun Retexture'  re-texture mod.

To keep with the original theme as New Vegas Nailer this will work as a sort of attachment pack(ish) mod for the Grease gun.

Brief Lore Stuff:
Developed by the East Coast division the MKII was set to be successor to the popular Nailer MKI.
Due to complications with worker strikes the initial launch was set back multiple times, it was said workers were under paid along with unsafe working conditions. H&H did finally get the Nailer MKII to launch but sadley due to the bombs dropping the shipments never got past the Springfield Massachusetts, New Hampshire & Rhode Island regions.
The shipments were found by Wastelanders & local Raiders.

Known issue:
Hand clips through the base receiver, unfortunately I am unable to adjust animations but anyone is welcome to release a animation mod for the Nailer MKII.
Due to not being able to adjust/edit collisions either you may come across some funkiness when the gun is dropped.

Features:
Comes with a custom ammo type H&H Nails.
Craftable ammo at a chemistry station
Nailer will spawn at level 25 on some Raiders & Raider bosses.
Ammo will spawn at level 15 in tool & other containers.
Gun & ammo is also added to vendor level list in Diamond city (Myrna & Arturo), Good Neighbor (Daisy & KL-E-0), Nuka World vendors & some caravan merchants. 
Custom ammo box textures.
Mostly uses 1 & 2K textures.
Has both single shot and full auto receiver options.

Static spawn can be found in the back of a van at the Natick Substation, which is West of Natick Police station.
Warning you may have to fight off a few Deathclaws and a Behemoth. 

Credits: 
Main one. Animations and some balance stuff is from DeadPool2099's Grease gun mod. Grease Gun SMG install is a must for the Nailer to work
Custom metal shaders by ajhakra. ajhakra's Cubemaps
a_blind_man for his level list injector tutorial/script. Leveled List Injection Toolbox

Software used:
Blender.
Substance Painter 2020.
Outfit Studio
Nifskope.
Material Editor.
GIMP (DDS conversion)
Clip Studio Paint.

Permission Stuff:
Anyone is welcome to add attachments or make re-balance patches, just don't forget to credit me. 

I would like to give my thanks to:
Degenerate Dak for doing a Alpha damage test & his tutorials on how to make mods for Fallout 4.
The Rizzler for his in-depth tutorials on YouTube.
JKRuse for his cheat sheet on how to tweak attachments (Found in Degenerate Daks Discord).