1- Open HMT and select the map
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2- Scroll down until you see [proj] projectile. Open it
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3- Select any weapon you want to change is bullet. I'll take the pistol.
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4- Press the swap button on top of the screen ( Before you press the swap button , copy the meta code in a safe place ). Then , choose the bullet you want. ( every bullet are in the little menu). I'll take Scorpion\tank shell
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5- After , press save and try it. Here's the result
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This is how you change projectile , hope you liked it.
p.s : if your tired of shooting tank bullet or any bullet you pick , pick the meta you saved earlier and paste it over your new meta.