.357 Marlin 1849 brass looks odd

[Stack]

I just got a nice little Marlin 1894 in 38 and .357. Shoots nice but there's an ugly black soot mark on the brass but just on one side from the case mouth back about half way down the case. I only shot .38 special Remington factory 130 grain loads so I wouldn't think ammo would be the problem. Any suggestions?

 

[RugerBob]

I usually only get that from lite loads , not factory loads. Not enough pressure building up to expand the brass and you get soot-blow back.

 

[stonecoldy]

Stack, you'll have that just as Ruger Bob stated-not a problem.
Brush out the chamber well if you shoot alot of 38 Specials and want to shoot the slightly longer 357 mag cartridges. You can get a bit of fouling in there, which can make it more difficult to chamber the mag cartridges and possibly push pressures up. Please ignore this if you're already aware of that.
That model Marlin is really enjoyable to shoot. Good choice of a gun. Love shooting mine.

 

[Stack]

Thanks guys. I was a little worried but feel your advice is solid. The plinking will continue!

 

[goon]

I've had this a lot shooting .38's in .357's. Like the man says, you're just not getting enough pressure to swell the case out in the chamber. No worries. As Dave McCracken puts it - BA/UU/R.