The most common cause of rifles that were once good shooters going terrible is probably dirty barrels. That could occur every ten shots or every hundred shots, depending on your gun. Cleaning your rifle after each trip to the range, assuming that you shoot a few hundred rounds, is a good idea if you want to be on the safe side.
You should clean your rifle before the bore becomes so dirty that it negatively impacts accuracy, according to thebest firearm lubricant. The most common cause of rifles that were once good shooters going terrible is probably dirty barrels. That could occur every ten shots or every hundred shots, depending on your gun. Cleaning your rifle after each trip to the range, assuming that you shoot a few hundred rounds, is a good idea if you want to be on the safe side.