I have no scientific reasoning behind my preference of hand lapping, just that (now with benefit of bore scope) I can have more infinite control over process than I could with simply firing a series of abrasive bullets blindly down bore. Looking forward to an evaluation of TFF based on actual pics and chrono comparison.
Now for the promised tale of woe, BS (Before Scope)
I've come to expect stellar accuracy from Savage rifles, based on my limited experience with five (IIRC) different Savage rifles. Therefore, I was surprised by the poor accuracy delivered by a like new .308 Scout. I consider it a personal challenge to squeeze the most accuracy from such rifles, usually with some success. This one, however, didn't like anything I put through it, including many different proven target handloads and even stooped to trying a box of factory ammo (Federal Match).
Since the rifle was pre-owned, and having experienced the propensity of my other Savage rifles to be very efficient at collecting copper/carbon fouling, while producing sub moa groups, I wondered if it had a carbon ring and proceeded to work in that direction (without benefit of bore scope).
All my usual chemical cleaning methods were used until clean white patches resulted, yet accuracy, at best, hovered around 2 moa, with an occasional 1.75 just to tease. The longer it dragged on, the more I was convinced it was hard carbon and the more determined I became to get it out.
Using JB Paste mixed w/Kroil on a patch on bronze brush, alternating w/some old Gold Medalion from smallbore days, I began scrubbing the bore.....for days. A dozen or more strokes/day, but patches kept coming out black.
About the time I was beginning to wonder if the black was metal, not carbon, Brownell's ran a special on Lyman Bore Scopes. I broke down and ordered one and my doubts were confirmed. I had rounded off the sharp edges of the lands w/the aggressive lapping.
Lapping with various abrasives can produce beneficial results, but I prefer to do so with benefit of a bore scope.
The good news is, that I did finally find one load the rifle likes and will still shoot sub moa 5 shot groups with 125 gr. NBT w/H4895 @ 2910 fps, fortunately a very effective bullet/load for a dedicated coyote rifle. Any faster and groups open up. These two groups are only 3 shots each to zero after mounting a different scope.
Regards,
hps