Here's an example datapack I created for a flamethrower mechanic. I'll walk you through the functions here: I defined the flamethrower as a fire charge with a custom name. I'll mention how to change the item when we reach that function. For now, this is the give command for the firecharge (chat): /give @s minecraft:fire_charge[minecraft:custom_name='{"text":"Flamethrower","color":"gold","italic":false}'] tick.mcfunction: execute as @a if items entity @s weapon.mainhand minecraft:fire_charge[minecraft:custom_name='{"text":"Flamethrower","color":"gold","italic":false}'] at @s positioned ~ ~1.3 ~ positioned ^ ^ ^0.5 run function flamethrower:cast with entity @s If any player is holding the flamethrower item, it runs a function called cast.mcfunction. If you want to change the flamethrower item, replace minecraft:fire_charge[minecraft:custom_name='{"text":"Flamethrower","color":"gold","italic":false}'] with the item of your choice. cast.mcfunction is a raycasting function, meaning it is recursive and creates a straight line in the direction the player is looking: $playsound minecraft:block.fire.extinguish master @a[nbt={UUID:$(UUID)}] ~ ~ ~ 0.1 particle flame ~ ~ ~ 0.01 0.01 0.01 0.02 5 particle small_flame ~ ~ ~ 0.01 0.01 0.01 0.02 5 execute unless block ~ ~-1 ~ air unless block ~ ~-1 ~ water unless block ~ ~-1 ~ lava run fill ~ ~ ~ ~ ~ ~ fire replace air execute unless block ~ ~-1 ~ air unless block ~ ~-1 ~ water unless block ~ ~-1 ~ lava run fill ~ ~ ~ ~ ~ ~ fire replace short_grass execute unless block ~ ~ ~ air unless block ~ ~ ~ water run return fail $execute unless entity @a[nbt={UUID:$(UUID)},distance=..10,limit=1] run return fail $execute if block ~ ~ ~ air positioned ^ ^ ^1 run function flamethrower:cast {UUID:$(UUID)} I set the limit to 10 blocks in the 7th line (distance=..10). This can be changed by simply replacing it with the desired (e.g. 50 block limit is ..50) The functions plays a sounds effect (one I though was appropriate but which you may want to change, up to you) and creates fire particles following the raycast. If the block underneath it is grass or air, it will replace it with fire. This can be expanded to replace more blocks with fire (e.g. snow), you would just need to add more lines like this: execute unless block ~ ~-1 ~ air unless block ~ ~-1 ~ water unless block ~ ~-1 ~ lava run fill ~ ~ ~ ~ ~ ~ fire replace Where is your desired block. Finally the function checks the distance to the player which executed the command. If they are more than the minimum distance away, the flame stops. Otherwise, it keeps going. If you have any questions or if something does not work as intended, feel free to reach out. Hope this helps! More on reddit.com

Looks like Mo' guns https://www.curseforge.com/minecraft/mc-mods/moguns More on reddit.com

Here are the downloads for the data pack and resource pack . More on reddit.com

Hanz, get ze flamethrower More on reddit.com