This depends on what club you’ll be shooting at. Mostly because that’ll determine how far you’re going to have to shoot and what calibers you’ll be allowed.
Here are my opinions on factory class groundhog rifles and I’d think it’s the majority opinion. The 223 fast twists, that’d be 9 & faster, with the 70g+ bullets are usually the most accurate of the common factory chamberings. If you’re only going to have 1 factory gun it’d be the one to have. But once you get to 500 and beyond the 308 with its’ bigger easier to see holes and better BC may catch up depending on the conditions. The 243 offers little advantage in either the ability to see holes or BC,factory 9.25 twist) & IMO is in general less accurate than the 223. On average at most clubs out of any 10 shoots, I’d guess the 223 would be the preferable caliber in 6 or 7 of the 10 shoots. The 308 the other 3 or 4. There was only 1 of the 8 St. Thomas Shoots,200, 300, &400) that wasn’t won by a 223 last year. All top 3 agg winners shot 223s. Tuesday shoots were more varied for different reasons. But there too 223s dominated overall. A 223 LRPV won Mayberry’s,100, 200, & 300) Factory agg. New forum member Joe Pellegrene won Mifflin’s Factory agg with a 12 twist 223 Cooper.
But remember this isn’t like IBS short range. The accuracy of the rifles varies a lot more and they’re much more fickle than custom rifles. I’ve shoot Savages in factory class for some time now. And out of the last 15 or so heavy barrel Savages I’ve had they varied from .4â€-.8†rifles. If you’re lucky enough to get a very good shooting gun, it doesn’t matter what caliber it is. I’ve seen 22-250s, 243s, & 7-08s beside the regular 223s & 308s that shoot outstanding. This for a factory class gun would be ½†or under average 5 shot groups. You get any factory class gun that you can do that with regular and eventually you’ll come out on top.
To sum it up I’d say:
First check the club's rules you plan on shooting at before you choose a make and caliber.
If you’re going to shoot 100,200, & 300 yards at Mifflin I’d gamble on a slow twist 223. But who knows when that range may change to longer yardages.
200, 300 & 400 at St Thomas I’d get a 223 9 or 7 twist.
200, 300, & 500 at Mifflin I’d check with them before getting a 6BR Savage or Cooper,only place I know of where BRs or PPCs are allowed in Factory Class) or a good solid stocked 308 or again a fast twist 223.
200, 300, & 540 at Ship a fast twist 223 or good stocked 308.
South Fork is the only other shoot I’m familiar with and that’s a slightly different game because of no sighters and I’d just be guessing on what to do there.
Bill