Proper ratchet, extention & socket. You'll also need a pipe to fit over the ratchet handle, a hammer, some PB Blaster spray & a vice.

Block the breechplug hole & spray PB Blaster down the bore. Keep spraying until you count 15 seconds off the clock. Let it sit 24 hours. Put the towel-wrapped gun in a vise & use jerky hits with hammer on the pipe. First go tighter... yes tighter. Now go in reverse. Use CVA Breechplug & Nipple Grease. Only hand-tighten next time. Crack the seal on it after every several shots... then hand-tighten again. When you are finished shooting & the rifle is real warm, turn the plug loose two turns until you get home.