I've got 2 SPS stocks myself someone can have. The Hogue stock is not bedded buy does have aluminum pillars which the SPS does not. I just personally do not like the rounded grip or the rubber feel to it. Either one is going to need replacing to get consistent results.
I have seen several 18" barrels reach 1000 yards however it was with a pretty hot load and the right powder. A 26" barrel would make it a little easier to get the needed speed if that is what the OP is planning on doing. The length of barrel should not make any difference in accuracy.
Here are a couple .308 that I have had that might give you some ideas of what your looking for. There are lots of good rifles out there and you won't go wrong with any of them.
Surgeon .308 w/ Broughton barrel and HS Stock
SPS Varmint with a HS Precision stock.
700 Police (basically same gun as above but with a fluted barrel)
Factory SPS Tactical with the Hogue stock
Hot powder and a light load aren't required for consistent shots at 1000yds with an 18" barrel.
http://www.youtube.com/watch?v=15qj032UJ1I
From his reply to a comment in this video:
Lowlight said:2575fps with that lot of Cor Bon 175gr, I have gotten as much as 2605fps with factory 175gr ammo. I can get more if I use 170gr HPS from Lapua, and you can get more with a 155gr load. Anyway you slice it, from 2575fps up...
Its a good theory, but its being proven wrong more and more nowadays.
Both of mine are 22" long - I've only stretched one of them before (waiting on getting my son's out when we can get access to yardage again), but it was with 168gr FGMM BTHP factory ammo and I had no issues.
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