Greetings everyone. I'm new to long range shooting and the Sniper's Hide Forum. I recently invested in a Tikka TAC A1 that is chambered in .260 Remington, and I'm loving it. After shooting 400 rounds through the barrel in about a month, I decided to clean it. Soon after I took my PVA Jet4 muzzle brake off, I noticed the carbon build-up. Well, after soaking a handful of 3 inch patches with Bore Tech C4 and leaving it on the muzzle for about 30 minutes, I proceeded to wipe off the carbon. As you can see by the image, the black nitride came off the crown. Given that I'm a newbie, I'm not sure if I actually "damaged' the crown. Can someone please let me know if I did so? Thank you in advance for providing insight to this issue.