Ever seen this?

[flatlander]

I have an old 96 swede I picked up several years ago trading, and found what appeared to me to be corrosion for the last 8-10" of the barrel.  I haven't done anything to it except fit a new stock on it thinking I could possibly sporterize it since the barrel was cruddy, but nothing reversible so far. I picked up some wipeout for some of my other guns, and it worked great. So a couple of days ago, I shot some down the swede just for fun. The foam that came out of the muzzle was immediately blue, which I thought odd. I wiped it down after about an hour and the patches were so blue they were almost black. I wiped it until the patches came out clean, then hit it with wipeout again and left it overnight. Same thing: heavy blue.  But now, the area that looked like corrosion is gone, and it seems the area I was looking at wasn't corrosion, but HEAVY copper buildup. Anyone ever seen that in a swede?
Also, the barrel is stamped on the RH side out by the muzzle: CAI ST. A. VT.  with caliber markings underneath (6.5x55)   Anyone enlighten me on those markings? It is a 29" barrel, and the gun is a Carl Gustav 1906. Should I hold off on the sporterizing after all?

[Wynn]

The markings near the muzzle are the importers stamp required by the Feds since 1968. That is the old Century Arms International import stamp. They were/are? headquartered in St. Albans, Vermont. Copper fouling is common when using jacketed ammo depending on how many rounds are fired without cleaning with a copper solvent. Certain factors such as bullet diameter can add or decrease how rapid it builds up. I clean all my rifles annually with a good copper solvent if I have shot them more than 50 rounds or so. It appears your Swede may never have had a copper solvent cleaning which is not uncommon in milsurps.

Far more important is routine cleaning using water or proper water based solvent (a couple of wet patches of Windex with ammonia will get rid of the salts and minimize copper buildup) for corrosive primer residue soon after shooting using any milsurp ammo, although this is less of a problem with Swedes. Most if not all Swedish milsurp ammo was non corrosive but why risk a good bore?
I would never cut up a unaltered Swede. They aint making them anymore and they are increasing in value rapidly in their original configuration.

[flatlander]

Apparently this one has been shot quite a bit in the past, but I haven't shot it because of the bore. I didn't have a problem chopping the swede when I thought the barrel was bad, but since it turns out to be good, I most likely will sell it off and get either another project gun or just something else all together. I really like the 6.5x55 round, though. Nice to shoot and a great deer round.

[rockbilly]

flatlander.  Over the years I have sportrized at least 100 Sweds.  I currently have three in progress, but I think these will be the last. 

I agree with wynn to some extent.  If the gun is a numbers matching gun, then DO NOT alter it.  Keep the gun 100% military, or limit modifications to those that can be converted back to military easily.  If the gun is not a numbers matching gun, then it has little or no collector value, and will not likely increase in value.