After I practice and confirm zero, for hunting season, I wipe down the rifle, and rubber band the finger of a nitrile glove over the muzzle. This stays in place, keeping out snow, ice, rain, etc.,until the end of the seaon, or until a shot is taken. Pressure of exiting gas blows out finger before bullet exits muzzle. There seems to be no practical effect on accuracy. Bore gets a cleaning at the end of the season.

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George