Please note: you need to download GTA V Weapon Data which made by fkngoob due to ancient data corrupt my gameplay
Also after replace weapon.dat, you need to replace default.ide to avoid game crash due to game cannot understand what animation supposed to that weapon.

Copy and paste this lines in weapon.dat made by fkngoob:
$ SPAS12 INSTANT_HIT 120 120 351 -1 3 rifle 8 40 0.75 -0.06 0.22 0 0 1.4 1 6 16 7 6 16 7 35 7001
$ SPAS12 INSTANT_HIT 120 120 351 -1 3 rifle 8 40 0.75 -0.06 0.22 1 200 1.8 1 6 16 7 6 16 7 35 7011
$ SPAS12 INSTANT_HIT 120 120 351 -1 3 rifle 8 40 0.75 -0.06 0.22 2 999 2 1.2 6 16 7 6 16 7 35 7031

If you don't copy this line, mods will not work correctly.

After that, you must rename .txt to .dat, which a thing that I forget mention to this flaw from previous mods.
Then rename default.ide to .txt, copy and paste this line:
351, shotgspa, shotgspa, rifle, 1, 50, 0

Then save, rename again from .txt to .ide, or if you do by just modified weapon.dat but not for default.ide, game will crash.

I recommend use God Mode mods for CLEO from gtagarage, use for kill aggressive drivers from cheat with infinite ammo and never wanted for more fun.
But don't play with this (I mean aggressive drivers from cheat) over 40 minutes, it cause a problems.