History is your friend...
Canister shot metal containers filled with small iron balls, stones, glass and nails had much the same idea as using grapeshot cannonballs. This was specifically designed to kill sailors on the decks of enemy vessels.
And what worked for big black powder guns worked for smaller ones too. Many early accounts of blunderbusses describe them as being loaded with all sorts of scrap.
Mindset - Skillset - Toolset. In that order!
Attitude and skill will get you through times of no gear, better than gear will get you through times of no attitude and no skill.