I have a suggestion.
Please don't take this wrong, but are you holding correct for the type of rifle? have someone snap a pic of your sighting the rifle. you MAY just be canted or have a different hold than others (how the rifle was designed to be held). when you look at the pic, if you are using the right technique, then go for the repairs. I've seem new recruits be shooting all over the place and then we showed their hold versus what the regs recommend, and they adjusted just that one point of hold, it all came together.
I tend to snug down on a rifle, it's just me, and i always have to lower my rear sight on the older rifles with iron sights to get zeroed. my brother shoots more heads up, kind of like the European style, and his point of hold works for him. I can't shoot his zero and he can't shoot mine.
Any way just a suggestion as I went through a similar issue