I have a Remington 700, .243 caliber I've owned for 23 years. Over the years I used the gun primarily to hunt and would clean the barrel onece a year after hunting season. The routine was to dry brush the bore then run solvent and then dry patch until clean. I woul leave a thin coat of gun oil for storage until the following year. I probably averaged 10 rounds per year through the gun. I recently got into reloading and improving accuracy and have shot some good sub MOA groups with the rifle but only after the gun was what I considered clean. After three shot groups, with time for the barrel to cool between shots, the groups would begin to spread out. I began to wonder if the barrel was fouling easily so I looked into cleaning with JB compound. I ran the JB through the bore and the patch was solid black. Several dry patches later the barrel was clean or so I thought. I ran another patch of JB through the bore and it cam out as black as the first one. I have since tried various solvents and ultimately the patches come out white. I next tried some Iosso bore past and basically did a repeat of the JB routine above. I know I've run at least 100 patches through the bore and there is still black fouling coming out. Is there anything that will get 23 years of crap out of this bore or is the stuffed baked on for good?