heavy lead fowling in 12 gauge

[on_one_wheel]

So I'v given the 12 gauge a good clean after using a few 1 oz rifled slugs and noticed some pretty serious lead fowling. It was coming out in massive flakes about 5mm wide 10mm long at least twice as thick as alloy foil. The gun has fixed ic chokes, with 20" tubes, and the loads were mostly Federal power shock 2 3/4" and a copple of Whinchester super X deer 3" thrown in. 10 slugs and 12 BB's since the last clean. So my question is has anyone else noticed fowling that bad after using slugs.

[padaro]

Man, that is some huge fouling

[Old Fart]

Hey mate,

Probably a bit late now since you've cleaned it, might be to wait until your next shoot, but...

I see two flakes of lead there, is it always two?

If you look down the dirty barrel, are the flakes deposited in the same place(s)? Or are they random?

[AlanK]

The chokes could be the cause.

Full diameter slugs going through the chokes will loose a little lead...

As long as everything cleans off and is accurate though, it shouldn't be a problem.

[Norton]

I'd just try one type of cartridge, then check for fouling.

Try the next one and repeat...

I've seen a few where the lubricant of a particular slug didn't agree with a particular barrel and caused the flaking. Switching to a different brand and the problem went away.