I know my way around a 30BR pretty well.
What I will tell you is my opinion based on shooting in countless Matches through the year, and being known to, on occasion, do pretty well.
It is true that you can shoot an entire 100/200 yard Grand Agg, that is around 80 rounds with sighters, without cleaning, and the darn thing will shoot just as good on the last target as the first.
I have done this on occasion, but lately I have been cleaning every other target. Each t target will usually be around 8 to 9 shots.
I use nothing but Butches Bore Shine. I brush it around 10 back and forth strokes, stopping the brush the instant it clears the crown. I then use as many saturated patches as needed untill they are coming out clean. Once again, stop that darned rod the instant it clears the crown.
I then dry it before going back to the line for the next relay.
After the Match, I clean just as before. I NEVER take a rifle home dirty.
One of he advantages we have in Short Range Benchrest is we can clean often, not ever allowing all that crud to accumulate in the barrel.
Maybe that’s why I never have to use ISSO, Sweets, Barrel Paste, or any thing else. I started using Butches decades ago when Butch first came up with his concoction.
I don’t care what YouTube video is pushing what theory, or what product. I know what works in a Short Range BENCHREST Rifle.
Now, keep in mind, This does not apply to Rifles in Disciplines that shoot 200 to 300 rounds where the shooter cannot clean the barrel.
Also, I shoot only Krieger and Bartlien Cut Rifled Barrels. They tend to clean really well. I have no idea how to clean a button or hammer forged barrel.
Now, for the big question. Do I use a borescope to see if the barrel is clean.
No. I go by what Mr Krieger said years ago before he succumbed to the bore scope craze and cleaning product manufacturers.
That being, Cut rifled barrels, by their very nature, have multitudes of small linear tool marks that will fill up with a copper and burned residue wash. They are so small you never see them. Leave that in those tiny marks. After the first couple of rounds after cleaning, they will be back anyway.
As a note, the single most important items in any cleaning regiment is use a good bore guide, and stop that brush or jag the instant it clears the crown.