I shoot monthly NRL22, regional NRL22X and am soon to attend my 4th of 5 NRL22 National Championship match in a few weeks.
Don Smith custom CZ 455. Use a Mike Lucas bore guide. Pro-Shot micro steel 42" rifle .22-.26 Cal. rod with 20 cal and/or 22 cal jags (depending upon patch size). 50-50 mix of Kroil and Shooter's Choice is my solvent of choice followed by Montana Rimfire Blend. Patch 3-4 times to remove fouling. Let soak at least 5-10 minutes; sometimes over night if i'm no hurry. Quality 22 cal bronze brush for bore. 6mm bronze or nylon brush, dipped in same 50-50 mix of Kroil and Shooter's Choice for chamber. Patch out to dry. Don Smith told me never more than 250 rounds between cleaning. I try but sometimes fail at not exceeding that number; especially when i'm having fun shooting.
Try to keep chamber clean, removing carbon so you don't get the dreaded carbon donut in front of the case mouth. If left uncleaned for too long a ring of "pits" might form in the chamber right in front of the case mouth. Once it's there their is no cure other than to clean it more often or change barrels. I've seen it with quality Kidd and Lilja as well as factory CZ, barrels. The ring of pits can accumulate a carbon ring fast. That carbon ring will quickly (30 seconds or so) harden and when you send a 1st round shot, it will squeeze/swag the bullets .224" bullet down under bore diameter, allowing gas to pass the bullet causing a low velocity, low point of impact. After the first shot, the carbon ring is softened and subsequent rounds will not squeeze/swag down nor have low point of impacts. I've see this with lead, target grade ammo, not copper clad bullets. I typically see POI as much as 2 to 4 moa low. Cost me 4th place in the 1st NRL22 Championship match where a 25-35 yd aspirin sized target is missed, bumping me to 10th since my first round impact in 6 of the courses of fire had very small targets for the first target. I would literally watch my bullet fly toward the steel target, missing below it. I've discussed this at length with my buddy at Vudoo 22 rifles and he concurs.
Alan
