I agree with Cowboy, you are running a risk of damaging your bore or crown by over-cleaning. This would only be a worst case scenario, most doubtful that you are or have hurting anything, just increasing the risk of doing so.
I would sincerely doubt that your barrel needs cleaning until 40 or more rounds. We fired 39 rounds through my 6.5-284 yesterday and one of the last three shot groups went inside 0.3". Seems to me that the higher the velocity the more cleaning is required. Load reasonably and your less likely to build up copper fouling if your bore is a good one. I like to keep track of how many patches I use during a cleaning job, how much blue I see if any. Prefer to minimize bronze brushing to about 6-8 strokes and clean the bristles after each use.
Best is to develope a cleaning routine that works for you. If cleaning after 15 shots makes you feel good, then what the heck. I have barrels that keep shooting nicely with 80+ rounds through them, some that need cleaning every 40. Some pickup almost no copper, some need special attention to get all the copper out. Had a barrel that shot terrible after I thoroughly cleaned it - until about a dozen rounds, needed to foul it good for it to shoot.
I have been using TM Solution. Sure is doing a fine job on my rifles - only need one solution which makes life simpler. Available from Sinclair Int.
