There is getting to be a decent selection for aftermarket parts for savages as well, but remmy is still king. A factory remmy with a good chassis will serve most people well, that is what I started out on. The weakest point of most factory bolt actions is the stock.
Eventually got to the point where I could shoot as well as the rifle and upgraded. As long as the round count is not excessively high, remmies hold a decent value (better than some others) if for nothing more than the serial numbered receiver for people starting custom jobs (how I unloaded mine with 1500 rounds down the tube for trade value of $500)
Your barrel length concern:
.308s tend to gain the vast majority of their velocity within the first 16-18 inches, and everything after that is peanuts. The only thing you are gaining with a barrel longer than 18" is weight and a few FPS of muzzle velocity. Velocity has nearly nothing to do with accuracy, aside from a very negligible gain in wind bucking. I push a 20" .308 to 1000m with no problems, as do many others with 16 or 18 inch barrels. At the ranges you are talking about, you have zero reasons to have anything longer than 18"
As with everything, it all depends on what you want to do with it...
For an intermediate range (300-600m) platform for learning, I would suggest a .223. Match grade .223 will run you much cheaper than .308 (if you handload, then this doesn't matter as much), and external ballistics at the ranges you are talking about are farely comparable. Terminal ballistics for .223 do become questionable beyond 300 or so, if you care about such things.
As already mentioned: is $1000 for just the boomstick or for the whole package?
The SPS Tac would work fine. Start out with that and quality glass and rings (NF, S&B, USO) since glass can't be upgraded, buy once cry once (lower quality glass doesn't tend to hold its value for resale) Get matching dials and reticule, and parallax control. Zero stops are great, but you will likely never need it at the ranges mentioned. A fixed 10x would work fine for you (mine is 3.5-15X and it is always on 15X, no reason to dial down), don't worry about getting super high mag (>~20X), and don't waste your money on FFP (there are only a few shooters in the world who actually make use of it, for everyone else it is just a status symbol). Use blue loctite: Set relief, mount, lap, test, level mount, test, plum line, box test, and you are GTG.
If you're just gonna shoot off the bench or prone flat range style, the harris bipods will work, but so will a pack for much cheaper. If you want to get into some improvised positions in less than ideal circumstances, get an atlas.
If you stick with it, then eventually upgrade to a quality stock and custom bedding or chassis system, then you can worry about detachable mags (you don't need to worry about that now). Adjustable combs are the greatest thing since sliced bread and can help out a shooter of any skill level, adjustable length of pull is good too.
If you get to where you can outshoot the weapon, and want to upgrade down the road, then just trade it out (used custom jobs can be had for a steal, since everyone wants to build their own, even though it is insanely expensive and a pain in the ass). If you want to push out further, be sure to get a level.
