What I do is work up an accurate load at the range, clean about every three shots or so. Once I have established the load I will hunt with, (which usually takes more than one range session) then I completely clean the gun, and adjust the sights to a clean barrel by cleaning between each shot.
It does not take all that many shots, so cleaning between each shot is not the monumental task that it sounds like. Then you can hit the field with a clean gun, which will do more towards reliability then a dirty one!
I have also found that the follow-up, or second shot goes into the same group that the first shot from a clean barrel goes. At about shot three or four POI will begin to change.
I don't think, but I may be wrong, that one can really have a rifle that shoots to POA from a clean barrel, and then use it for target shooting without adjusting the sights. With all due respect to the fellow who hunts with a dirty barrel, I don't see that as a very good option either.
I think the best bet is to keep the hunting rifle sighted for a clean bore, and then get a smaller calibre, or the same calibre rifle for target shooting and plinking.
By the way, I find Hoppe's #9+ to be excellent for cleaning the barrel at the range, while sighting in.