I think the best answer is that it depends on the gun, and how clean "clean" is.

For instance, my Ruger M77VT MkII 22-250 will shoot <.75MOA for about 40-50 shots before accuracy starts to go south. However, after cleaning the crud out of it the accuracy actually gets WORSE before it gets better. What I mean is that if I clean it when the groups open up to 1 to 1.25MOA, after cleaning the next 3 to 4 shots will group into maybe 1.5-2.5MOA before settling back down to the usual .75MOA or less. However, the actual group position (mean point-of-impact) doesn't move much at all.

My best suggestion would be to take your cleaning kit out the the range with you and clean it out there in the middle of a shooting session. Keep track of your group size and POI before you clean, and then note where the shots go and if you have a group after you clean the bore. If the poi shifts significantly, I'd shoot several more shots and clean again. Then check the POI again after cleaning and see if it's consistant with the last clean barrel shot. If it "groups" with the other clean barrel shot then you COULD adjust the sights to make the POA match the clean bore POI which would allow you to hunt with a clean rifle.

The question I'd ask though is..."Why bother?"

Smokeless powder and modern primers are completely non-corrosive and non-hygroscopic (don't attract moisture), and the bore is unlikely to rust when as long as it's kept reasonably dry, so why bother going to all the trouble of hunting with a clean bore which could cause accuracy issues. There is nothing wrong with hunting with a fouled bore, and in fact, you have the advantage of knowing with certainty exactly where the bullet will hit when fired because the bore is the same as it was when you sighted it in.

I'd say just sight it in and leave it dirty.

Mike