HM's pictures tell all.
What ever your thoughts on cleaning, chemicals used, you really will not know what you are accomplishing until you get a bore scope.
Lyman II is a great bore scope. Also, recently I was gifted an $80 Teslong with the 90* angle lens. The Teslong plugs into your phone, lap top, I pad, etc. I used an old lap top.
The learning curve is fantastic to say the least. Each barrel is different, each load with it's particular speed will foul differently.
Shooters make many assumptions about their cleaning methods, and the $80 investment in the Teslong will add barrel life, and much better groups.
Couple of things I have learned:
A. Pro shot bronze bristle brushes are great, they are good for 100 strokes, buy them by the Dozen!
B. Two plastic brushes are great, Issio and Montana Extreme.
C. If you are not using a brush, you are carbon fouling your barrel. At some point, carbon gets so hard, you will not see the slightest amount of grey on a patch.
D. powders foul very differently. Consult the Heat Index Chart, hot buring powders cook the carbon on very fast.
Use a pair of calipers and measure the dia of your brush, get ready for a shock. Brushes need "spring" in them to scrub. When the "spring" is gone, you are just getting exercise.
Copper is easy to deal with, carbon fouling is THE real can of worms!
Vast majority of people do not want a gun cleaning hobby, they just want their barrel clean enough for their desired accuracy. More importantly, they do not want their barrels ruined prematurely from impossible to get out carbon fouling.
When HM"s products do not get a barrel clean, a few products will clean most barrels if they have not been ruined.
A. JB, and Montana Extreme copper cream are about the same, with the copper cream being easier to use. I use both of the above on 4 patches scrubbing back and forth in a short stroking method
https://www.midwayusa.com/product/1014782252?pid=331485
B. Flitz bore cleaner is more aggressive for moderate stubborn carbon that tough plastic and bronze bristle brushes will not remove, I can not stress this enough. 4 patches, short stroked, usually gets the job done for regular maintance.
https://www.ebay.com/itm/Flitz-Gun-Bore-Cleaner-7-6-oz-Bottle-/124218944821?hash=item1cec06ad35
C. For barrels that are really abused, very large cases where you are shooting nearly 100g of powder that is really cooked on, Sinclair makes two products that cuts though the carbon. This was told to me by a shooter that uses a 50 bmg for long range.
https://shop.brownells.com/gunsmith-tool...e2d5a51634b618d
600 and 800 grit to clean barrels with. This is an extreme case, use on rough Savage barrels, or any barrel that is rough making it all but impossible to clean. Use sparingly, and not for habitual use. Get them clean to begin with, then learn the frequency they need cleaning.
I have an old sporterized German 98 in 8mm, and a British 303 whose barrels like beyond horrible, to say the least. I clean them every 20 shots and they shoot a 1" group or less, plenty good enough for deer hunting.