If you indeed have a Bushnell 4200 6-24x50mm, you might have the older model and that one has less than 50 MOA of adjustment. I have attached a review of this scope, and the one tested had only 44 MOA of total adjustment.
https://www.snipercentral.com/bushnell4200.phtml
If this is your problem then you need a 0 MOA base or one sloped not more than 10 MOA. If your scope has only 44 MOA of TOTAL adjustment that's 22 MOA up and 22 MOA down, and with a 20 MOA base it takes that 20 MOA from the down adjustment to give you 42 MOA up and leaving only 2 MOA of down adjustment, in a perfect world.
The newer Bushnell Elite Tactical's do have more total adjustment, but the older 4200's do not.
Often you need 5-7 MOA of down adjustment just to sight in and it sure looks like that may be your problem....