Re: Tubbs Final Finish (recent users?)
I've tried it on a couple factory barrels. I'd never use it on a custom tube. Also I typically only use half the kit. 1 shot course and clean, 2 shots course and clean, 2 shots course and clean then repeat for the fine. I also only use it once, I won't use it after the first time as "maintenance".
My experience has been this, accuracy did not get worse, but in all honesty if it improved the best groups it was only by a small amount. I do think in at least one case it made the rifle significantly more accurate with a wider range of ammo. Ammo that shot poorly before using the kit shot better after the kit. However, the groups of the most accurate ammo before using the kit stayed virtually identical. Mostly I noticed that the rifle was easier to clean, fouled less, and a slight bit of velocity was gained.
Since I've seen little or any accuracy gain using the kit, I only use it for rifles that seem to foul really quickly/badly. That and honestly with the amount of tool marks and such in factory tubes I doubt you could damage one with the kit. So for the $40 for the kit it's not much $ to stick into a rifle, esp. if you use only half the kit.
That said I've yet to hear of anyone using the kit and getting worse accuracy so I'm sure it accelerates the barrel wear a bit but on something like a .308 with a lot of barrel life anyway I don't think it's a big deal.