"The Oil that Creeps" into areas as small as one-one millionth of an inch. The best stuff on the planet for breaking rusted bolts and nuts. If the barrel is THAT full of rust, I'd be concerned about accuracy. Remember, rust is metal gone bad...if you remove that much metal from your bore you probably don't have any rifling left...you probably have a .52 cal. smoothbore.
Guns Have Only Two Enemies-Rust and Politicians
"The United States Constitution (c) 1791 - All Rights Reserved"
If Guns Kill, Do Pencils Mis-spell Words?
Pain is Weakness Leaving the Body - USMC
"Qui desiderat pacem, praeparet bellum"