You're learning a good basic lesson early. Anytime you change ammo components, you will need to check where they hit on a target!
This means ammo brands, bullet styles, bullet weights, even a different brand of primer. Some loads will hit sort of in the same place as another, but this is only a coincidence, normally changing any part of a load can cause a different point of impact.
Save yourself a lot of frustration, try out several different loads you think fit your hunting/shooting needs. Now, that your scope setting is getting hits somewhere on the paper, don't change the scope settings again until you've selected the best shot group load. Then set your scope to that load only.
After you've selected a load, shoot a clean target and allow your barrel to cool down in between shots. As the barrel heats up it can cause the bullets to scatter on a target. Some people time their shots at the range allowing 3 to 5 minutes minimum between shots when testing to choose a load.
HAPPY HUNTING
Point of impact differences at 100y is as a result of barrel vibrations and not bullet drag. If your barrel is touching the stock as in 'not free' floated that could cause stringing. Glass bedding and free floating could help consistency. Did you give the barrel time to cool? If you did not give the barrel time to cool take your time and shoot a 'very' slow 3 shot group and see if it make a difference. I would recommend a good rear bag also.
Hot barrels don’t “walk” shots or “scatter” shots unless there is something wrong with the barrel. A properly stress relieved barrel will continue placing rounds within the true group size until it melts (until it gets so hot that you have barrel droop).
