Let’s assume the barrel cleans decent (no abnormal fouling etc…) not a high round count etc…not chambered in some really overbore capacity cartridge that isn’t being cleaned properly etc…
Ammo is good, gunsmithing work is good, scope is good etc…they guy behind the trigger is doing his job and reading the wind etc…
There are a lot of variables!
If you start shooting and as the barrel warms up you see the shots string/wander on you…don‘t touch the sights. Let it cool. Then start shooting again…if the groups/shots again seem to string on you…that to me is a sign of the barrel having residual stress in the blank and or a bow to it. Bow is our term for being bent basically. You never want to straighten a barrel with a bow in it. If this is really happening you cannot fix it.
Carbon fiber? Or steel shooting in cold conditions even in normal to hot temps….ever wonder why a F class shooter uses a mirage shield on his barrel? To keep the mirage from distorting your view thru the scope. This is another factor.
Land, terrain, moisture…conditions can effect you as well.
If all those are ruled out…then yes the barrel could have residual stress in the blank and or bowed. Even good button barrel makers who restress relieve the blank before turning….there is no guarantee you got all the residual stress out of it.
Later, Frank