Re: 22-250 or 243 700 Yard Woodchuck Caliber
If I was going to stay with the .22 caliber then I'd go with the .22-250 AI with 1-8 twist. Nothing slower than 1-9 for sure. When the range for the .22 centerfire(s) ncreases then I think the weight of the projectile should increase also. This gives them a little more stability and "thump" on out there.
There may be some guys out there than will tell you the .22-250 is good to 1000 yds. It might be, but not in my hands. Too much of a stacked deck at LR. Even the lowly, but tastey, GroundHog deserves clean, humane kills.
Go with the 6mm's. I shoot a standard .243 and with bullets heavier than 75gn, it does great. The 55 and 65gn bullets aren't much better than the .22 CF's in my opinion. I like the 95gn Ballistic Tip as my go to bullet for varmints, predators and deer. My 11yr old was smacking my 500yd gong Saturday with my .243 using this bullet ahead of 44.0gn of Vhitavuori N560 and BR2's.
When the barrel goes out I'm going with a .243AI barrel and play with that for a while. Good luck. JohnnyK.
"The pleasure you get from life is equal to the attitude you put into it."