- I would say .223 would give you more use. Basic trigger technique should be the same for any caliber you shoot. A .223 is affordable to use often, and you will have more legitimate targets for it. Hunting seasons are brief... bottles and gophers are fair game all year round.
- I think you would find more choices in premium .308 match-grade ammo, since it is a mainstay of long-range shooting competition.
- However, if your goal is to train as a sharpshooter, I'm not sure if you would see the benefits from using match .308 in a 700 Tactical SPS.
- I hear they have good accuracy, but for serious precision shooting, it really does take more than a $500 stock factory Remington to squeeze the higher accuracy potential out of the .308 - A precision rifle and custom tuning handloads for it.
- If you don't need to get THAT precise, The accuracy potential of the 700 Tactical might be a better fit for the inherent performance of a .223. Within the range of the .223 factory loads, the 700 Tactical should be sufficient.
- Are you married to .308 and .223? There are cartridges that arguably have ballistics that are better suited to long-range accuracy.. less drift and drop. No accuracy would not world-class from a factory rifle in your price range, but would probably give an edge over both the .308 and .223
I can think of 6.5x55, .270 Winchester.... a variety of 6mm rounds. You always hear people say that the .308 is a cartridge that just tends to be accurate. While there may be something to what they say, 7mm-08 and especially .260 Rem seem to be more efficient in the same case. They don't lose energy as quickly and fly flatter and are less affected by wind. There are of course other options, but these are the more common ones. The .260 is a caliber that I personally fancy, I've been impressed every time I shot one. You see 6.5mm bullets cropping up in serious shooting matches all over, and the .260 just has the convenience of being a modified .308 case.