you have had the same results that I have experienced. I have a Ithaca hawkin I bought in 1985 and I don't think the lock on it has ever been removed. It shoots so well that I dare not touch it unless I abolutely have to.I just took the lock out of one of my caplock rifles for the first time since I bought it new over 5 years ago. It had absolutely no fouling or powder residue on it & looked like it had just been installed at the factory. Even had some of the original oil visible. Is this unusual? I see where some here clean the lock every time they shoot. Why do their's get dirty & mine doesn't? It is a Lyman GPR. Are they different some how?