So after a really long wait I finally got my form 4 approved. took the silencerco SS sparrow our for the weekend and put 1000 rds through it. All I can say is "take your earplugs out so that you can enjoy it" cleaning it was another matter. I First tried the regular solvents, IE hopps #9. that did nothing , then I found out that vinegar eats lead, So I soaked the parts in straight white vinegar, which loosened the lead. 15 min later and the silencer looked new inside. So i just took it apart for the second time, however, I coated the internals with TC Bore Butter after cleaning it the first time. Wow. the build-up just fell off. Hats off to the guys at silencerco for a great design and a silencer that will outlast me. I fully plan to put 52,000 rounds per year down the hole of this baby. Being solid Stainless I doubt that I will have any problems, will keep you guys posted.