I've been noticing over time that both the 10 rd and 17 rd mags have been getting scratches on the back of them. The sides and front are perctly fine, but only the back of each have long streaks of scratches running down from top to bottom. I've only shot about 200 rounds through the SR9c with the 17 rd mag, and only 10 rounds with the 10 round mag. Is Ruger's QC that bad? I've not seen this happen to other handguns I've owned. Not even close to what I see on the SR9c. We're talking from black to bare shiny metal. Is this normal wear for Ruger SR9 and SR9c mags?