I had the same problem with my 17hmr all it turned out to be was the scope we would get it zero'd then take it out the next day make a slight change and boom it would be hitting just everywhere. Put an old 3-9 we had sitting in the closet and not it's dead on. Check and make sure that everything on the gun is screwed down tight and then if you still have the problem try a different scope, while sighting it shoot off a good rest like a table or even prone also make sure your resting the gun on something soft never shoot your gun off of a hard surface.
"come on you sons of b***hs! do you want to live forever?" Sergeant Daniel Daly, USMC, Belleau Wood France June 6th 1918
"You can be as mad as a mad dog at the way things went. You could swear, curse the fates, but when it comes to the end, you have to let go" Benjamin Button