This might come across as rude, but I'm honestly trying to help out here, so, take it for what it is, I don't mean to offend.
Seeing your results with the 175 Blackies, I suggest you save the money to get a chassis, and invest in practice ammo and/or a class. With that rifle, and certainly with that scope, those 20 rounds should've given you a group half that size (not counting the occasional flyer. It happens). You've got something wrong going on in your fundamentals, is my guess.
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