A couple things. First I only clean the bore and a few inches forward of the bore after shooting. I also us M-Pro 7. I run a wet patch and let it sit for 20 minutes and then run dry patches through it.
I'm more concerned about a carbon ring than I am about copper fouling.

I only give it a full cleaning on heavy shooting days or around 350-400 rounds. I typically have to shoot 4 or 5 rounds to foul the barrel to get back to my original zero. I have no experience with the cleaning agents you're using, but if you're barrel is like mine and many others you may have to shoot some rounds to foul the barrel to tighten your groups back up.

Second, I shoot Hornady 140 ELD-M exclusively in my 6.5 Creed. I load my own ammo and have found that they like .030-.040 jump in my rifle as well as my buddy's. I'm running a Defiance actioned full custom with a Bartlein 26" barrel and he is shooting a Savage Stealth. We both get the best results loading that far off the lands. I've also found the best accuracy nodes for the 140 ELD M have been just under 2800 fps. The barrels I have shot out lasted around 2500 rounds or so. And even then there was no loss in accuracy, just lost speed. I never chase the lands. I have my barrels cut to SAMMI freebore and never adjust my seating die from then on. I cant imagine the 147's would be that much different than the 140's.

Thank you Sig Marine and swage. I believe I have really learned something.

Aside from all of the self inflicted pain I caused myself by chasing numbers and changing stuff, what really worked was cleaning the barrel.

I did use the J-B Bore cleaner coupled with Kroil until all of the copper and carbon were out.

It took 3 rounds to get back to semi-normal velocities and acceptable groups but after about 40 rounds, it is shooting just as good as ever and even a little better. I shot several .4 MOA groups today using the new lot of powder and original charge weights and velocities are within a 2-3 fps of the old lot. Probably just the difference in temperatures between a few days ago and this evening.

What I think I learned is this: Running a patch with cleaner followed by a bore brush and then dry patches (maybe a few iterations of that) keeps the barrel shooting well until it doesn't. The signs are random flyers, larger groups and, possibly, changes in velocity too. Then its time for a more serious cleaning.

For now, all's well that ends!

Thanks for a little more education,
Henryrifle