The 22-250 is a bore-fouling son of a gun. My brother in law must have used a 55 gal drum of copper solvents keeping his clean. Get some of the JB Bore Paste & Bore Shine, polish the crap out of your bore, and then just clean it after you shoot it. For sure don't leave the aggressive cleaners in over night - read the instructions & heed. I use Montana Extreme Copper Killer if I want to get it all out, otherwise, Hoppe's Bench Rest Copper Solvent does very well. The Montana Extreme was developed by 50 caliber (BMG) shooters with serious fouling issues, and believe me, it will get it out. Keep the fumes away from your eyes, and the stuff off your skin, though.