Looks like you had a fun day!
I think the second three ammo groups are around 2", I bet we can come up with a few things can to get you down to your 1" goal. With the 1-4x20mm scope and the good scope mount, you have shown there is great potential.
The first couple of things are pretty simple. Using a 20 round mag, shorten the length of the bipod, to allow less side to side "wiggle". the second is an old USMC trick. They would take a sock (with no holes in it), and fill it about 3/4 full with sand. (I use an empty shot bag with used tumbler media to keep the weight down) Place that under the shoulder end of the butt, or under the pistol grip. Use the pistol grip and your "strong side" hand to pull the rifle into your shoulder and your "off side" hand to grasp the sock or bag. As you bring the crosshair (or aiming dot) onto the aim point, squeeze the bag to stabilize the rear end of the rifle. This makes working on your breath control easier. You also might try to use the smallest target you can clearly see at 100 yards. ( I found 3/4" price tags in the middle of the black Bullseye make a good aim point. I don't know if your eyes are up to that, if not try 1". The idea is the saying "Aim small, miss small!" These are easy and don't cost a whole lot.
After a few tries with the smaller target you may or may not want to try just using the plane, blank, back side of the target with the aim points spaced about 4 to 5 inches apart. [This just saves paper and trips down range.
] I would bet that after a good session you will find that one of those ammos, shoots better the others and is under your 1" goal.
Have fun!
Ivan