Seasoning: I used to believe in seasoning hook line and sinker. This came from my centerfire shooting days where the barrel needs to be bare-metal cleaned before it's shot (that is, brand-new), then cleaned fairly thoroughly after each 5 to 20 rounds through the new barrel. This was definitely the case with a .270 WSM I bought a few years ago. Was only fair accuracy until 60-80 rounds were through it. Now I have 1/4 to 1/2 MOA.
The idea after then was that the pores in the metal (yes, stainless steel has microscopic pores) need to be filled with fouling to achieve optimum accuracy. You'll know that benchrest competition shooters almost always fire 2 "fouling shots" before a shoot. They also often say cleaning down to "bare metal" sets you back to a brand-new barrel. Many BR shooters, and even our own sniper squadrons will do a bare-minimum clean like run a bore snake down a few times then call it good.
Of course, it might be different with BP smokepoles and not smokeless.
On a 20+ year old Lyman Trade Rifle I learned on, I'd clean the bore with HOT soapy water, dry completely, then treat with bore butter or oxyoke. That old bore would drive tacks at 50 yards.
I followed the same regimen with a .54-cal Rice barrel, until every time I wiped my bore, whether 5 hours, 5 days or 5 months after the last time I shot I'd get brown on my patches.
Certainly, that might be the vegetable base in the bore butter oxidizing, but I was always worried about rust.
Now, I just use warm water, no soap, clean till patches are mostly (say, 98%) clean, dry completely, then treat with Sheath, like Ohio JOe says, or another similar Beechwood Casey product called "Barricade".
About 3 days after the clean I'll run another Barricade patch, then about once a month year-round if I haven't shot.
