Ok so you got a lemon, same as automobiles.
I have a 2010 mdel SS ruger mini HB with tuning barrel in .223 that will put holes all on and around a quarter all day at 300 yds.= 1.5 inch That is the best semi auto I have ever owned and I've seen a few over the last 40 years in many different calibers. I've posted pictures of it and the targets in the AR posts.

It is better to be judged by 12 than to be carried by 6.