I clean at the end of each yardage. At 100 yds, that will be from 50-60 shots, including the warm up match, sighters and record shots. At 200, it's about 70-80 rounds. This is a 30BR so for other cartridges (6PPC, etc), the cleaning intervals will be different.
-Two wet patches of Accelerator
-Fill the bore with Wipe Out foam
Then I let it sit while I reload my fired cases, etc. After about 20 minutes, patch out the Wipe Out, bore mop the chamber, clean the lug area and head back out with the gun and set wind flags for the 200.
Same routine at the end of the day, except I refill the bore with Wipe Out foam (no Accelerator used). The next day at home, I'll patch that out and get in there with the bore scope to see if there any carbon at the end of the neck area.