I clean my rifle(s) after each firing, whether one round or 300 as I am never sure how long it will be sitting in the safe.
Cleaning procedure/solvent depends on the particular rifle. I have an old Savage .338 that is my go-to hunting rifle (shoots sub moa groups consistently) that picks up quite a lot of copper (bore looks great but obviously must not be real slick). I usually use a nylon brush soaked in Hopes Bench Rest 5-10 strokes and let sit 30 min. or so then dry patch to remove powder fouling. Then hit it w/wipeout foam and let sit overnight and dry patch it again. If I plan to hunt again within a week or so, I run a patch soaked in Kroil thru the bore and put it away. If rifle won't be used in the near future, I use Shooter's Choice FP10 or CLP.
On rifles w/custom barrels (much smoother bore), the wipeout usually gets 'em clean without any other solvents. Wipeout is a bit slower in removing powder fouling than Hopes but does a great job on copper. The Hopes Benchrest is a bit more aggressive than regular Hopes on copper, but not so strong that you cannot leave it overnight on heavily fouled barrels.
Regards,
hm