Glock 17RTF new, shooting Xtreme plated 124gr FP at lower velocity using WW231 powder. Getting what I thought was leading in the barrel but would not come out with brushing, solvent nor Lewis lead remover. Finally tried some bore polishing compound from long ago and with some very vigorous effort removed the residue from the barrel. I still cannot figure if it was lead or some of the copper jacket or? Has anyone had an issue like this? I had planned on getting a LWD barrel anyway, but this has me stumped.