My Brother has a savage 223/ 20 ga combo gun. Last summer he went to shoot it and mistakenly loaded a 6x45 wildcat rnd into a 5.56
rifle the cartridge will chamber and fired it. He brought it back home because the spent rnd had to be tapper out with cleaning rod. Now I have been shooting it but I can get no accuracy out of it. It is keyholeing at 50 yards I have cleaned it with bore scrubber for lead and copper fouling, but so far it has not helped. Do you think that firing 1 rnd that is almost 1/2 a mm larger than the bore would permanently damage the barrel and destroy the accuracy.