Can't edit damage on Non-GenericGuns (Grenades,,MiningDrill,Chainsaw,CombatKnife,PowerHammer)

[RobinTeens]

Using CraftTweaker to edit gun damages, using:
import mods.techguns.GunStats;
GunStats.setWeaponStat("handcannon","DAMAGE",20);
It works very well.

However, when editing Grenades, using this:
GunStats.setWeaponStat("fraggrenade","DAMAGE",50);
GunStats.setWeaponStat("fraggrenade","DAMAGE_MIN",50);
I get this on minecraft text:
techgun.items.guns.GenericGrenade cannot be cast to techguns.items.guns.GenericGun

I change those grenades order to the bottom, but instead getting error from other gun types (non-genericguns).
Here's the error log:

crafttweaker.log

> [INITIALIZATION][CLIENT][ERROR] [crafttweaker]: Error executing {[0:crafttweaker]: Techgun_Tweak_Damage.zs}: techguns.items.tools.TGSword cannot be cast to techguns.items.guns.GenericGun
> java.lang.ClassCastException: techguns.items.tools.TGSword cannot be cast to techguns.items.guns.GenericGun
> 	at techguns.plugins.crafttweaker.GunStatTweaker$setGunStatAction.<init>(GunStatTweaker.java:40)
> 	at techguns.plugins.crafttweaker.GunStatTweaker.setWeaponStat(GunStatTweaker.java:18)
> 	at Techgun_Tweak_Damage.__script__(Techgun_Tweak_Damage.zs:72)
> 	at __ZenMain__.run(Techgun_Tweak_Damage)
> 	at crafttweaker.runtime.CrTTweaker.loadScript(CrTTweaker.java:240)
> 	at crafttweaker.runtime.CrTTweaker.loadScript(CrTTweaker.java:105)
> 	at crafttweaker.mc1120.events.CommonEventHandler.registerRecipes(CommonEventHandler.java:71)
> 	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_716_CommonEventHandler_registerRecipes_Register.invoke(.dynamic)
> 	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
> 	at net.minecraftforge.fml.common.eventhandler.EventBus$1.invoke(EventBus.java:144)
> 	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182)
> 	at net.minecraftforge.registries.GameData.fireRegistryEvents(GameData.java:857)
> 	at net.minecraftforge.common.crafting.CraftingHelper.loadRecipes(CraftingHelper.java:636)
> 	at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:747)
> 	at net.minecraftforge.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:336)
> 	at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:535)
> 	at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:378)
> 	at net.minecraft.client.main.Main.main(SourceFile:123)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> 	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> 	at java.lang.reflect.Method.invoke(Method.java:497)
> 	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
> 	at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Lookin deeper on GunStatTweaker.java,, it doesn't have import for other guns/weapons, except:
import techguns.items.guns.GenericGun;
Is that what preventing me to edit damage on non-GenericGuns?
Any idea how to implement damage tweaking to other non-GenericGuns?