Agree 100% with Nate. I started shooting across the course and prone matches last year. I had a bit of a background, but was still effectively brand new. After the first match, you get the swing of things and the only regret you'll have is not starting years earlier. Just get out and try it....what's the worst that could happen?
My first time shooting past 400 yards was in a match. I had done a little homework and was on paper on my first shot. I could have not done any homework, and guys there would have had me on paper pretty easily. Electronic targets make getting dialed in almost too easy.
As far as F-class goes, there are some beginner level shooters with essentially hunting rifles, and then there are a handful of members that are some of the best in the country/world in their respective game. Both have more fun than should be allowed at a match. For across the course (service rifle/match rifle), there's a couple of high-master level shooters that regularly come to monthly matches, several master and expert level shooters, and a few beginners. I've not seen anyone (2nd match shooters nor national champion-level shooters) be anything but helpful to new folks at any time, in any match, at any distance.
There are a couple of options for a guy with an AR looking to stretch it's legs at Atterbury.
One is at a mid-range "prone" match. NRA came out with a "mid-range AR tactical" class last year....it's basically just an AR with a max 12 power scope shooting mag-length ammo at a normal prone target (1 MOA X-ring, 2 MOA 10 ring, etc). All shots will be from prone, using a bi-pod or front rest and a rear bag if you want. This is shot at 300, 500, and 600 yards. 20 rounds in 20 minutes. You get sighters at each yard line before your shots-for-record.
The other option is unique to CIHPRS/Atterbury this year, and designed specifically to get more people out with their AR's and expose them to this kind of shooting. It's shot alongside those shooting "Across the Course" (standing, sitting, prone), but instead shot all prone and using smaller targets. 200 yards slow fire (20 rounds in 20 minutes), 200 yards rapid fire (2 strings of 10 shots in 60 seconds per string), 300 yards rapid fire (2 strings of 10 shots in 70 seconds per string), and slow fire at 600 yards (20 rounds in 20 minutes). I don't recall what the target sizes are exactly, but they are smaller than the regular prone targets. You'll get 2 sighters at each yard line.
Bring a few boxes of Federal Gold Medal Match (77 or 69 gr Sierra Matchkings) if shooting factory ammo, or bring handloads using SMK's or similar, and from a 200 yard zero, come up 3.5 MOA to get to 300 yards, 10 MOA to get to 500 yards, and 14.5 MOA to get to 600 yards. Add 1-1.5 MOA to all those if you're starting with a 100 yard zero. Maybe a touch more at 600 if you're using 69's. You'll be on paper elevation-wise. You've got a +/- 6 MOA at 300, and you're still in the scoring rings. The electronic targets will register way outside of that. Ask someone if the wind is blowing more than 15 MPH for a SWAG wind-call at the time. Otherwise, just send one and adjust accordingly. It's not rocket surgery to get on paper.
Pick a wind flag and watch only that flag. Bring a notebook to record your data and make notes of what you see and learn as far as elevation and wind....especially the frickin' wind.
If not for being out of the country for work until later this year, I'd offer to show you the ropes myself at a match. A shooting caddy, if you will. Just go anyway, enjoy, and learn. It's fun. It's addicting. It's inexpe.....well...it's not as expensive as some hobbies.
