Removing jacketed fouling from barrel For Cast Bullet Use

[.22-5-40]

Hello, Sir.  I have read many different opinions on this..some say clean until every particle of jacket bullet fouling is removed..others claim it doesn't matter..I am now thinking it might depend on bore condition?  If a bore has shiny land tops, but light frosting in grooves (bright but not quite shiny)..I wonder if cleaning until no more blue shows on patch is necessary before trying cast?  Thank you!

[Veral]

  There is a remote possibility that jacket fouling could be an asset to cast bullets,   The condition would be if a bore were rough and small at the muzzle when clean, and if jacket fouling built up a smear over the bore roughness.    In other words, jacket fouling has no effect on cast bullet performance until it builds up enough to change barrel diameter, creating a loose at the muzzle condition.

  Ditto for jacketed bullet accuracy through a fouled bore.  Whenever jacketed bullet accuracy begins falling off, one can push an LBT push through slug through the barrel and learn that bullets are losing guidence as they approach the muzzle.

  The two worst conditions of jacket fouling I've encountered was a Springfiled 30-06 which probably hadn't been cleaned in at least 50 years.  A push through revealed  a diameter of .300 just forward of the chamber,  with rifling almost invisible.  The neighbor who brought the gun over did so at my request after he told me that his bullets blew up on the surface of a deers chest cavity.    ----   Intense heating of the bullet jacket caused enough weakening that the bullets popped on impact.   

  The second case was a 308 which literally had ribbons of jacket fouling curled out and visable when I looked through the barrel.

  Don't sweat it if your gun  barrel is jacket fouled, but accurate enough with cast to suit you, but if not, clean, and preferably run a push through through so you know what the barrel condition and dimensional variations are.  Those last two are the factors which determine whether cast can be made to shoot well.

[.22-5-40]

Thank you Veral..I had always wondered why copper fouling was detrimental in some bores..and not in others.  changing bore dimensions makes the most sense.

[Veral]

  Yes indeed, it makes sense, but when one actually measures the amount of fouling, all doubt is removed.    And when one finds that lightly fouled bores shoot just fine, he can listen to no other opinion.

  More about the two neighbors heavily fouled barrels.  The first one shot one deer, at about 100 yards,  in the ribs, and recovered the animal after considerable tracking.

  The second was shooting Hornady 30 cal 110 gr RN bullets with a hot load, which he and his wife had used for years for deer.  They aimed for the neck right behind the ears if the animal was close enough, for the chest for longer shots.  We were visiting them when he told me that he had shot four deer so far, about a week into the season, had knocked all of them down and had drawn blood but all ran off and he wasn't able to track them down.  This was an old man and a very experianced hunter.  I tried to scrub the barrel out with scouring powder that evening, to no avail, so told him to just keep the barrel wet with 3 in one oil, which was the only fine oil he had.  (He lived 50 miles from us so I wasn't about to do all the running home and back to properly clean his gun.  He killed a deer the next day, getting deep enough penetration to do the job instantly, with a chest hit, and another a few days later with similar results. 

  I told him to be sure to clean the barrel with a good bore cleaner, untiil the patches came out clean.  To my surprise, the next year he told me that they had both killed deer with the dirty barrel again.  He so no reason to clean when a little oil solved the only problem he had with.

  I've personally  known at least  4 other jacketed bullet hunters with similar problems caused by a foulded barrel.    One very important thing to understand is that the bullets killed clean with decent penetration if the shot was close, like 40 yards or less, but the bullets became explosive on contact when ranges were 100 yards plus.    This because only the jacket surface was near molten at close range, but after traveling out to some distence the heat penetrated the jacket material to full depth, softening it dramatically.