When working on a load or sighting in a new gun, I shoot a lot of "one shot groups." That's specifically because I want the same thing you do.
Fire one shot doing everything you know how to make it as accurate as possible. If it's off the center mark, go ahead and shoot a couple of more shots to see if it's an accuracy issue or sight-in problem.
Go ahead and clean the gun to bring it back to the condition it will be in for your first shot on a hunt. Shoot your one shot group again.
I want that first shot to go exactly where I point it from a clean bore, no matter what any subsequent shots do from a fouled bore.
And yeah, I use compressed air (CO2) to clear the bore each night, followed by a brush into the breech to make sure no powder remains, then a lubed patch. Load er up again in the morning and go back to hunting.
Range shooting, group shooting, and competitions are fun diversions, but they shouldn't distract you from the need for that very first shot to do it's job on the day of the hunt.