I have to hand it to Krieger barrel company. I just broke in a new 6mm 13.5" twist for the upcoming season and I'm happy to report that it is hands down the best barrel I have ever seen. It broke in with one shot and has yet to produce one blue patch! I have tried several loads in it with several powders and it is shooting in the "zeros" already at 100 yards with many of them. It is very easy to tune and even easier to clean. I have broken-in tons of barrels and have never seen one this good. Whatever Krieger is doing nowdays, I hope they keep it up for years to come!!