barrel fouling- why the plastic residue?

[bluebayou]

I have a beater shotgun, a Mossberg Maverick.  This is my first and only shotgun at this time. 

After firing today, I noticed that the barrel was fouled with streaking from the wad I am assuming.  I sprayed Gunscrubber through the barrel to loosen carbon and plastic streaks.  When I ran a brush through I came out with plastic bits...almost torn strips of plastic from the end of the chamber. 

I had assumed that the forcing cone was a gradual taper, but this barrel just has a step that reduces from the chamber to the barrel.  Is this common on lower end shotguns or are higher dollar shotguns gradually tapered down at the end of the chamber?

I never paid attention to this before.  The shotgun functions fine.  I guess.  I was just surprised to see so much plastic come out of the barrel. 

When a forcing cone is polished is this "step" radiused off or smoothed out?  Would one of those Flex-Hone things make any difference to this shotgun?  Would it foul less or make a better pattern?

It is just a 18.5" cylinder bore barrel.  I get 6 double ought pellets at 25 yards into a paper plate right now. 

[Questor]

Don't worry about it. A high quality chrome plated bore, like in the Berettas, helps reduce foulding but doesn't eliminate it. We had a Mossberg for my son and it fouled more than my gun, but they all foul. I use a bronze brush wrapped with bronze wool to get rid of the fouling. It's quick and easy. I just put a bit of solvent on the bronze wool. Someone here posted that Hoppes Benchrest solvent is the best solvent for plastic fouling, but I haven't tried it yet myself.

Our Mossberg was the youth pump in 20 gauge. Great gun. My son outgrew it and we sold it. It was one of the best guns I've ever known. He was able to hunt everything from woodcock to whitetails with that gun. The receiver was tapped for a Weaver mount. It had a good tang safety. It patterned well, was reliable, had screw-in chokes, was accurate with certain brands of slugs (Rottweil was best). Mossberg makes a fine product.

[Tn Jim]

In my Mossberg 930 Field, the cheap Winchester Universal shells from Walmart leave a LOT of plastic fouling. The Winchester AA loads I use for hunting leave very little behind. Also, if your Maverick is newer, the bore may be a little rough. It will smooth out after use and cleaning several times. Have you tried different shells?

[kiddekop]

I took a 12g shotgun cleaning rod and broke off the plastic handle screwed an old 12g bronze brush into the end,wrapped it with 4 ought steelwool ,dampened it with hoppes #9,chucked the end into my electric drill and power cleaned my shotgun barrels which removes all of the plastic,lead & powder fouling rapidly.I use it on my custom Win Mod 12 12g trap shotgun,my ithaca mod 37 16g , rem 870 & 11-87 barrels.