From my understanding of how his powers work he should be able to charge things in a single touch. So he could just have a custom firearm that would allow the ammo to glance his finger each time it’s loaded, allowing it to be charged. It doesn’t even have to be a actually gun, since a BB gun, hunting slingshot, or crossbow would be just as good.
In the comics he actually gets something like this, might happen in the show pretty soon. Won’t be too specific bc spoilers.