I've never used a chronograph, but around 69 thru 71, my best 5 shot group was 5/16" at 100 yards with a Rem, 788 chambered for the 22-250. Never was able to do better than that, but managed a fair number of 5 shot groups under 1/2" a couple of them were 3/8".
I decided to try my luck at 200 yards hoping I could hold the same MOA. I was taken aback when my first group was 5/8". I never did better than 5/8" at 200 yards after that, but after going to the range 6-8 more times, I managed to get about 25% of my 5 shot groups just as small. i also managed to get about 45% between 3/4 - 7/8" 5 shot groups. I'm recalling from memory, but I don't think I had more than 2-3 groups go over an inch at 200 yards. The load was 35.5 gr 4064 behind a 55 grain Speer Spitzer. I know that only because, when I dug out all my reloading paraphernalia, the labels on my ammo boxes told me what load I was using.
My experience wasn't very scientific, but the MOA of the groups were so consistently better, using the same load, I could never come up with a better explanation. I have to believe something is responsible for those better groups & more consistent groups.
Unfortunately I was laid off the same year and had to move to Illinos to find a job. Never found a range close enough until recently to shoot from a bench. Two more years after that, I got divorced & was too poor to buy reloading supplies for a long time. As it is now I drive 100 miles round trip each time I want to shoot.
To top it all off, I live in Illinois, which really sucks even with the new "Concealed Carry" law that's supposed to be enacted this coming January.
If anyone has an explanation better than mine, I'd like to hear about it.