dirty is subjective.
1 round is dirtier than 100% bare metal clean. SO is 400 rounds.
How different rifles perform with different amounts of carbon and copper depends on many factors.
best bet is to clean a rifle to bare metal then watch accuracy and keep round count until you see accuracy falling off.
Then you know what your window of accuracy is and when you need to clean.
2 wet patches of butches,
patch with acetone till it comes out clean then bore scope to see copper build up.
JB to bare metal then a patch of kroil followed by a dry patch.
Butch's is so old school I cant believe people still use it..........
I like Cortina but the way he cleans a rifle with 6 or 7 different things is ridiculous.....
Use Bore Tech Eliminator and be done......yes I have 2 bore scopes
