we drilled and tapped it for a 6-1mm #11 nipple but im going to put my musket nipple on it the next time we shoot it, the #11's are to small and often dropped at night when we are loading it. Just keep in mind the next time u see glow sticks flying over your house, you may have said something to make me mad and im zeroing in on ya . Its really fun to shoot, the biggest flame we got out of it was a blue/purple 12 foot long flame that mushroomed out at the end. Oh another awesome projectile, toilet paper rolled duck taped and stuffed with odd things. Shot also shoots well.