Hesse guns are not just known for poor accuracy, they are known to be Dangerous, and come from a company that sells trash then changes its names and sets up new shell companies to sell more trash.
I'm sorry you had to buy one of these, it will likely not function with any reliability if at all and I have no idea how it will group, or if it will just blow up because Hesse couldn't make anything to spec if his life depended on it, which I guess he's fine with since he's willing to risk yours.
If you can see if you can take it back to the dealer(I hope) and get your money back, if you want a HK91 you can try you luck with a CETME, most of them function, some have some issues, but at least they aren't dangerous. or for a little more money a PTR, the newer ones have tighter chambers for domestic .308 only, no surplus, but really nice, well built rifles, or an older used one which should have the more original military chamber.
I don't mean to bring you down off your new gun high, but I also don't want you to get hurt, financially or otherwise.