First off I'm a believer in 3 shot groups with a big game sporter barrel rifle and 5 shot with target/varmit barrel. This helps to isolate flyers, flinches, etc. Now the fact you shot 3 - 2 shot groups which repeated the exact same results you do have a grouping happening, which tells me it ain't a scope/mounting issue. If it were the shots would not be replicated so percisely, at least in my experience. I could also be optimistic to eliminate shooter and rest problems as it would be pretty amazing to see one chilly dip 3 second shots exactly after putting the first ones all 3" high. So my thoughts are either: Load or bedding issue at this point. Buying a secondary type of ammo is an easy check or comparison. The bedding issue can be in the form of stock touch when it heats up from the first firing. A test would be a dollar bill slid along both sides of the barrel channel when ambient and after a firing. If it changes or catchs you need to either hawg out the channel at the touch area (s) &/or have it pillared and glass bedded.

Try 3 shot groups, let it cool to ambient and then another 3 shot groups to follow. Outside temp changes the wait time, use your hand or touch to gauge when the barrel has adequately cooled. If sunny and hot letting it cool in the shade will minimize wait time.

good luck