It is a lot more visible on a stainless steel gun.
I also think the stuff hardens over time, as hundreds of times, while at the range, I fired a few boxes of 38 special and then a few boxes of 357 and never had a problem with cases extracting. Now, let it set for a few days and i am not so sure.
It also seems to me that fouling builds up on stainless steel guns quicker and is much harder to get off. I had a taurus m66 357 blued, and id go to the range, yadda yadda, come home and clean etc. I then picked up a Taurus Tracker (regular, not extra light)and i had to scrub three times as hard to get the cylinder clean, as well as other areas. I also had tons of carbon buildup on the outside of the ported/compensated barrel. I kinda figured taht buildup there wouldn't matter, as long as the holes stayed clear.
I just wonder if there is something I can put on beforehand, or something, that will prevent it from caking on so hard, either at the front of the cylinderholes, or on the ports