Strange lumpy fouling

[kawalekm]

Saw something this weekend that I have never ever seen before. Was shooting my regular #2 cast 358477 bullet loaded +P in .38 specials in my Marlin micro-groove rifle. After cleaning I spotted three very distinct black lumps towards the breech, about 3/4" ahead of the chamber. Tight cotton patches normally clean out all the leading, but this would could not even be removed with a brass brush.

I finally disassembled the rifle, and bent a paperclip to reach into the barrel. While looking down the barrel, after scrapping at the lumps for a while, they broke off one by one and fell out the muzzle of the barrel. It appeared to be lead, but I have never seen it lump like that before in my guns.

Anybody have any experience with this?
Michael

[44man]

Saw something this weekend that I have never ever seen before. Was shooting my regular #2 cast 358477 bullet loaded +P in .38 specials in my Marlin micro-groove rifle. After cleaning I spotted three very distinct black lumps towards the breech, about 3/4" ahead of the chamber. Tight cotton patches normally clean out all the leading, but this would could not even be removed with a brass brush.

I finally disassembled the rifle, and bent a paperclip to reach into the barrel. While looking down the barrel, after scrapping at the lumps for a while, they broke off one by one and fell out the muzzle of the barrel. It appeared to be lead, but I have never seen it lump like that before in my guns.

Anybody have any experience with this?
Michael
Sounds like you are skidding the rifling with boolits too soft and a powder too fast. Try water dropping the boolits if the alloy is no. 2. Let them age and harden. Try a slower powder.

[kir_kenix]

I would also try a harder alloy. I've found similar fouling in a fast twist 260 rem improved at top or near top end (for cast anyway) speeds. A switch to a harder alloy solved this problem.

[gray wolf]

Was shooting my regular #2 cast 358477 bullet loaded +P in .38 specials in my Marlin micro-groove rifle. After

If this was your regular load and it had not happend before a thought may be carbon build up grabbing lead and lube and amalgamating into a hard crusty PITA nasty looking substance.
Here in Maine we call it CRUD.