Re: Problem 700 SPS
I've had a couple 700 SPS cheapie rifles in standard calibers like 270, and I hesitate to say this under the circumstances, but they shot great with most ammo for what they cost...about 3/4 moa at 100 yards. The only upgrade I made to them was a Timney adjustable trigger since the Rem factory trigger is not adjustable and truly horrible. With a rifle that Cabela's sometimes sale prices down to almost $300 new, its certainly going to be a gamble from one to the next. It sounds like I got lucky with mine.
I'd have a good rifle smith run a scope down the bore and tell you what he sees with the rifling. Maybe some action work and a good hand lapping of the bore will do the trick. Otherwise you're looking at a trued action and custom barrel, as others have suggested. You might also want to try some more forgiving bullets like the original accubonds to see how they shoot.
If its any consolation, spending a lot of money on a factory rifle is no guarantee either. I bought a NIB Remington Sendero in 300 RUM and it just wouldn't shoot no matter what I tried. Sent it back to Remington for warranty work and they acknowledged a problem, claimed to have lapped the bore and re-crowned the barrel and sent it back. The test target they sent was pathetic. A three shot vertical string measuring 1 inch to closest edges was "within warranty". It sure didn't look like anything I'd call a 1" group. It never really shot much better and I ended up selling it with full disclosure and a slight loss. Now when I want a rifle for accurate shooting, its a custom build. When you get done adding up all the extra costs poured into the SPS, the only difference is that you'll spend more money and still not have the quality of a custom build when you're finished.