Loading the the 460 S&W

[Road_Clam]

I shot some H110 today.
I noticed with 44 grains, it got everything dirty AF, down the cases, all the way to the rim. Pic below.

But as I increased the charge it wasn't an issue anymore. 45.5 shot great. .

The bullets are .452 230g FMJ from RMR.

Look at how dirty those fired casings are. Some have grains of powder stuck to the side.

View attachment 632729

When you load light you don't get enough pressure to allow casing expansion to seal the cylinder , gasses are being blown backwards down along the OD of the casing and that's why you see soot. I would try loading right to max and see how that works.