Just got a new M&P9c, my first gun. The one peculier thing i notice about it is that around where the firing pin is, I can see a fairly clear brass colored imprint of the test round that was fired.

I can just barely make out that it was a Winchester round, which matches the test casing that came w/ the gun. After some light scrubing w/ Ballistol and a q-tip, it doesn't seem to come off. Is this normal and will it ever come off? Should i get some brass remover solvents?

Nothing unusual, with any gun. I would not be concerned. Enjoy your new gun; shoot it a lot. Post a range report.
Sonny

The subject of copper coming into contact with bare steel has been, discussed, cussed, ranted, well, you get the idea, on this forum without consensus.

Fact is, on a microscopic level, the copper actually goes into the steel and must be chemically cleaned to remove completely. The concept of clean depends on how you examine it, which is why people practically get into fistfights about whether a barrel is clean. A piece of steel that even looks perfectly clean will often produce considerable residue with a Foul-Out electro-chemical cleaning system.

The good news is that the residue you see on the frame of your gun is completely harmless.

__________________
Science plus Art