The Ackley version is not legal in F-Class. The rules say 'unimproved', IIRC.
You may seriously want to reconsider getting a straight taper barrel; it will seriously limit your choices for other components such as scope, stock and bipod. Medium Palma contour or a fluted heavy Palma contour will work fine.
Most .308 chambers are cut for considerably more 'clearance' than say, a 6 BR or something like that. The conventional wisdom is that since most .308 LR guns are traditionally shot in Palma,and now F-Class) on ranges where you are close to the ground... there should be some room for grit, debris, etc. Not saying I necessarily agree with that, personally, but thats the normal train of thought. One book that recently came out has a prominent figure in the world of Palma/LR shooting recommending as much as 10 thou,5 thou on each side of the neck) clearance. Thats a whole bunch more than I like, as it brings its own set of headaches come time to resize the cases. The point is, it does work and the gun can and will shoot very accurately like that.
Most of the match reamers,Palma, Obermeyer, etc.) tend to be in the .342-.344 neck diameter. A couple years ago at least Pac-Nor used JGS reamers and after much wrangling I got some of the reamer prints from them. The Obermeyer chamber should come w/ a neck that is .346 @ the base, .344 @ the mouth, a shorter leade and throat than their 'SAAMI' .308 Win chamber, and a somewhat steeper leade angle. The Palma chamber should measure .342, has an even shorter throat & leade, but a gentler leade angle. IIRC, the .337 nk chamber is the same as the Obermeyer but w/ a tighter neck.
For reference sake, my neck-turned Lapua cases measured .014" thickness, and my loaded rounds run right at .336". Fired dimensions of my cases are in the .342-.343" range. Other people are running Winchester brass, which is really thin, and have loaded rounds down in the .331-.332 range, yet still shoot some outstanding scores like that.
If you really want to get picky about it, I think there are some custom match .308 reamers available that have .335" neck diamter, specifically for neck turned Lapua brass, or a .334" diameter for a 'no-turn' neck for Winchester brass.
Or you can just get an Obermeyer or Palma chamber,I have no experience w/ the Obermeyer, so I'd lean towards the Palma myself) and have it throated for the bullets you want to use. One of my rifles has a WTC 95 chamber and shoots wonderfully. Only problem is the throat is still so short,after 2k rds) that I can only really use 155gr SMKs or Noslers. Another rifle I have has a 'special' match chamber; in talking w/ the 'smith it's essentially a Palma 95 reamer throated for a 175gr bullet,which works nicely for the longer 155gr VLDs also). I know agonizing over the details of a custom rifle build is half the fun,sure is for me), but...
Trust me on this: shooting F/TR, you can load ammo that will shoot disgustingly tiny vertical spread, using regular match chambers. We,Team Savage) did it using factory barrels. The wind doesn't care what reamer your gunsmith used, and will still kick your hind end all over the place.
