You are confusing accuracy and precision, and I suspect you are using a 6 o'clock hold with the 3 dot sights, not how they work, designed for quick target acquisition, front dot goes on the target, not great for precision target shooting, but usually with some practice can shoot fairly decent groups with the proper target background.
With the proper target picture, you would not be shooting so low, probably right where it should be. If it was still a bit low, 147gr will bring it up a bit more. Maybe the prior owner drifted the sights to zero for his shooting habits, it's not rocket science to drift a rear sight to correct for windage.
If you bought a used scoped rifle that was shooting a foot low and a foot right at 100m would you call it quits and call it garbage or adjust the scope? Cuz that's basically what you are going on about in this post.
read earlier post...12 oclock hold was done. and yes the gun is sold. he wanted it after reading all this.lol