This is open sights, yes? I’ll say, my eyesight sure ain’t what it used to be. Besides corrected & astigmatism, my left eye is 100% blind. I’m not so hot with open sights at 100yds. Out of the to 25 with a pistol & maybe 50 with rifle. But after that, I want an optic! 100yds, open sights, my groups would likely be the same minute of pie plate…regardless of rifle accuracy. You are posting pictures of the barrel bore with a “matter of fact” presumption that your accuracy should be far better, if not for the barrel’s fault. Do you have other 100yd groups with other rifles using open sights? Was the rifle in a rifle random rest?(the only way to take all human variance out of the equation & truly test accuracy) If not, what position & rest did you use? The throat looks good. Sharp edges & clear starting point.