Lead smears in Jericho barrel

[PerversPépère]

One of my friends shot some 45 Auto reloads through his full size Jericho pistol.
The Jericho sports a polygonal rifling barrel.
The reloads are 200gr. SWC moly lubed straight wheelweight bullets cast from a Saeco mould, seated atop 5.2 gr. of Titegroup.
He says he gets some lead "smears" in the barrel.
Is it caused by the polygonal rifling not being adapted to cast bullets or simply a need for a different lead mix with perhaps more tin in the WW mix as in a Lyman #2 formula?
Thanks to you all.
PP. 8-)

[JonB_in_Glencoe]

it could be that the boolit is undersized for a proper fit in the barrel.
also, Titegroup is a hot powder and has caused me some
lead fouling issues in 9mm luger.

I have 2 baby eagles (US version of Jericho)
one in 40 and one in 45.
once I got the boolits sized correctly,
I no longer had lead fouling issues.
Jon

[PerversPépère]

The bullets have been sized .451 in a Lyman lubesizer with green (moly) lube.
Do you think it could need .452" in that particular rifling?
PP.

[JonB_in_Glencoe]

you need to slug the bore to know for sure.

I personally believe the polygonal rifling is less conducive to lead fouling,
but if the boolit is under sized, it will lead up.
Jon