I used the Tubb's Final Finish System to break in a Bushmaster Varminter about five years ago. I can't say how the rifle shot prior to the treatment as it was a brand spanking new bore, but it was a solid half MOA rifle following the treatment. Even the Federal Factory 77grn BTHP Match loads, that were giving many fits at the time for high pressure, showed no signs of it in that treated Bushy, and considering the 1X9 twist, still shot solidly into three quarters MOA, and many times less.
Most importantly, the rifle took forever to foul. I never actually shot enough rounds through it in one sitting, to see accuracy fall off, and clean up was very easy. It's also true that there was a substantial difference in feel on the cleaning rod before and after the treatment. Prior to, the tight patch was a bit difficult to move down the bore. I had actually considered cutting the patches smaller to avoid any concerns with the rod bowing. Following it, the tight patch just seemed to glide down the bore like it was riding on a sheet of glass.
I hope this helps.
I have used the Final Finish bore conditioning kits and the TMS kits. Most I have used with factory barrels with the exception of one ER Shaw .270 barrel. They have shown improvement in accuracy in every case and ease of cleaning. I would not reccommend the complete kit on a hand lapped high end barrel but the TMS (throat maintanence system) would work in this case. The TMS bullets have a fine grit compound where as the bore conditioning kits have 5 different compounds, course to fine. Superior Shooting Systems, David Tubbs company now offers pre loaded kits. I have only used the load your own and the reccomended load is fast burning powder at the minimum load. The bullets that Tubbs uses to adhere the various compounds to are SMK's with the longer bearing surfaces. so if you have a twist rate that won't work with a heavy grain bullet don't worry about grouping them. The intent is to use the longest bearing surface possible for conditioning. I have conditioned .223s, .270, and .308s. I purchased the loaded .22 LR kit but haven't had a chance to try it yet.