To install with OpenIV you replace the provided 
w_pi_revolver and w_pi_revolver_mag files here:
 
GtaV\mods\update\x64\dlcpacks\mpapartment\dlc.rpf\x64\models\cdimages\weapons.rpf



And weaponanimations.meta weaponcomponents.meta and weaponrevolver.meta go in these two places:
 
GtaV\mods\update\x64\dlcpacks\mpapartment\dlc.rpf\common\data\ai
GtaV\mods\update\update.rpf\dlc_patch\mpapartment\common\data\ai



Credit goes to 420x420 for the idea and the model. I just setup the meta and uploaded the mod.

 Thanks for downloading.