Dwarves are much smarter an mechanical minded than orcs/Goblins. This would be fine without the 2 damage to you/a creature you control drawback (which is on Orcish/Goblin artillery more for flavour reasons than anything else). As it does 2 damage you may need to make it to activate.

I edited it a little. I still want it to deal some damage to the controller because the idea is that this is still an early firearm and not all that dependable.

looks better

Nice. The , activation cost means it's not strictly better than Orcish Artillery. I'd keep it as "to you" rather than "to you or a creature you control", though. The latter is almost meaningless, because it can usually be activated at EOT when the damage is about to wear off, or just hit itself to no effect unless the opponent has a burn spell.

Thanks everyone. I'll edit it as suggested.