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:

For AK-47:
$ AK47 INSTANT_HIT 900 900 355 -1 5 rifle 30 35 0.78 -0.06 0.13 0 0 0.45 1.3 7 9 7 7 9 7 99 7001
$ AK47 INSTANT_HIT 900 900 355 -1 5 rifle 30 35 0.78 -0.06 0.13 1 200 0.45 1.3 7 9 7 7 9 7 99 7011
$ AK47 INSTANT_HIT 900 900 355 -1 5 rifle 30 35 0.78 -0.06 0.13 2 999 0.45 1.3 7 9 7 7 9 7 99 7031

For M16:
$ M4 INSTANT_HIT 900 900 356 -1 5 rifle 30 35 0.74 -0.04 0.13 0 0 0.45 1.3 7 9 7 7 9 7 99 7001
$ M4 INSTANT_HIT 900 900 356 -1 5 rifle 30 35 0.74 -0.04 0.13 1 200 0.45 1.3 7 9 7 7 9 7 99 7011
$ M4 INSTANT_HIT 900 900 356 -1 5 rifle 30 35 0.74 -0.04 0.13 2 999 0.45 1.3 7 9 7 7 9 7 99 7031

Attention: if you are use for mission that enemies use AK-47 (especially Home Coming, Beat Down on B Dup and Grove 4 Life), you need unmodified stats on that weapons,
if yes, rename from .dat to .txt, then copy and paste backup stats:

$ AK47 INSTANT_HIT 65 65 355 -1 5 rifle 30 25 0.78 -0.06 0.13 0 0 0.4 0.9 6 10 7 6 10 7 99 7001
$ AK47 INSTANT_HIT 65 65 355 -1 5 rifle 30 25 0.78 -0.06 0.13 1 200 0.5 1 6 10 7 6 10 7 99 7011
$ AK47 INSTANT_HIT 65 65 355 -1 5 rifle 30 25 0.78 -0.06 0.13 2 999 0.6 1.1 6 10 7 6 10 7 99 7031

I recommend use God Mode mods for CLEO from gtagarage, use for kill aggressive drivers from cheat with infinite ammo for more fun.