I have heard that any amount of copper/guilding metal fouling in a barrel will really excentuate leading when switching to cast bullets.  I am trying to get a 7mm Remington rolling block cleaned so I can go back to lead bullets.   After 5 or 6  sessions of letting the solvent (Hoppe's #9) work overnight,  I am still getting green/blue indications of metal fouling.  I am beginning to wonder if you can ever completely get 100 years of metal fouling out of a barrel.   I shot cast bullets in this rifle for quite a few years, but switched back to jacketed.   I doubt that I ever got all the copper fouling out in the first place.   So now I am wondering just how "clean" of copper the barrel needs to be to prevent leading.   Anyone care to comment?

George

Wonders of chemistry ......

"GUNSLICK" marketed at one time, and still may, a "foaming copper remover", where you squirt some of the foam in the barrel and wipe it out some time later, like 30 min to an hour.   It dissolves copper fouling readily.   
"Fatty acids" attack copper without damaging steel -- witness the green "verdigris" that you get around copper rivets in leather holsters and other leather goods.

CHRIS.

My old deer gun was a Marlin 30-30  microgroove using jacket bullets and my small game load was the 3118 with a bit of unique. I never bothered to clean the bore  before shooting that load and it would shoot about an inch at 50 yd.

What I was asking, and a couple of you sort of answered, was if the copper fouling made leading more severe.  I've switched back and forth between cast and jacketed bullets and always tried to get a clean bore before switching either way.  Just wondering if it was worth all the effort.

George

George, is it possible you may be picking up that color from a brass jag or other item the Hoppe's may be reacting to.
Just a thought. The guys I hang around with swear by Bore Tech Eliminator bore cleaner and they shoot jacketed competitively.
Hope this may help.i don't worry with that issue as my rifles are dedicated to cast or jacketed depending on caliber.

Bob

I'm using a nylon brush and aluminum jag.   There's just 100+ years of copper fouling inthis rifle.  I'm still wondering if the copper fouling will cause leading if I don't get it all out?

George

Heck,  I thought you told me Arco was warmer than Salmon!!!   It was only 3 below this morning.   I was out shooting last Thursday.

The 7mm is cleaning up fairly well, but still getting a blue patch on the first wipe after sitting overnight.

George

  I can't bring myself to treat a rifle barrel like a iron skillet.  

   How much rifle barrel 'seasoning' is enough?  Too much?  What kind of crud? Shouldn't that matter?
   Grease with bits of lead (and a trace of ground glass from primers) and some carbon....  and maybe sulfur from BP...   
   What about those jacketed bullets...dissimilar metals in intimate contact, zero moisture.  No humidity, ever?  Is that possible?  To avoid something like galvanic erosion. 
  
   But greasy lead bullets, Over jacketed fouling.    
  Copper, zinc, lead, tin and possibly antimony;  coating carbon or stainless steel. Some powder fouling.  Some kinda grease.   A real witches' brew.   
    That oughta be ok.   Sure.  Some people who oughta know say so.   
  But.... it's not for me.  I need to know it's pretty darn clean.    'If' something's proves to be more accurate with a coating of lube in the bore; I do that. 
    
  Guess I'll never shoot a 250 bench rest;  and I'm fine with that. 
   

    I've certainly made my share of mistakes.  
  
  Years ago, I was pressed for time and stuck a perfect-appearing 22lr barrel in the safe without even a damp patch through the bore. Rushed off to work. Two days later it was severely rusted.  Badly pitted.  Not by some ancient ammo.  Just ordinary std. velocity stuff in common usage. Why? How? Not moisture, climate controlled and use desiccant packs...never a problem before or since.      
  I don't know.  

   Other people apparently never clean.  And apparently never have a problem.
  Hurrah!   Good for them.  

   Maybe I'm just one of those people who can screw up anything.