i am not a long time user of the hmr (only fired around 200 rounds through it) but i did give it a good clean last week with the rod , patches, brush, forest bore foam i done this 3 times letting the bore foam soak overnight and there was loads of the copper fouling removed so from now on i will use the rod on it after 50 or so shots. i have yet to try it on a target to see if the good clean has made a difference.