I use two ARs with WOA Varmint Uppers in 223 with 12 twist. I feed these 40 grain Hornady VMax at about 3500 fps. These cover out to about 400 yards till the wind comes up, and then I tend to run them within the first 300 yards. I use SWFA 3-15x FFP scopes with an MOA reticle on these two. That is because... If I sit a rookie down on it, I have to be able to drop the magnification since rookies tend to struggle finding the target. I click the dope for them and tell them the wind hold to keep it simple. The system works well when they can find the right target. For the longer shots, I used to run Rem 700 Sendero but they are no longer being made, so I have a pair of Savage 12 Low Profile Varmint rigs in 223 with 7 twist and feed them 77 TMK. These do much better in the wind and out to 600 yards. I run the NF NXS 8-32 with MOAR-T reticle on these and like them very much. For the mornings before the winds come up, I cover the first 200 yards with a Ruger Precision Rimfire in 17 HMR being fed with CCI 17 gr and I use the reticle for the hold. These 17 HMR are very easy to run out to 200 yards using point blank system where you just hold over or under. You also don't waste centerfire ammo on rookies till they start ramping up the learning curve. Everyone who has tried this rig loves it. You can see your hits with all of these rigs and follow up shots are easy if you miss your wind call. I think I will try a .204 WOA Varmint Upper next year just for fun. I have used my friend's 204 truck gun on coyotes and think 204 will be great on prairie dogs out to 400 yards in a WOA Varmint Upper with a 24" heavy profile bbl. For most rookies, I would advise starting with a 17 HMR and 223 for their first season, unless they are already experienced at wind shooting. This is a volume shooting sport and shooting small targets in the wind at distance isn't like shooting their deer rifle once or twice per year.