The big question is what will you be doing with this rifle?? Banging gongs at 500-1000 yds, medium/large game hunting, or a little of both.
I practice some long range distances, and I want my rifle to perform, but that’s all done as preparation for hunting situations. So if it’s a hunting rig you’re wanting build, I would approach it differently than a competition or long range target rifle, although there is often some overlap.
There are some real pros that can advise on building something that will excel at long range for targets, whether competitively or just for fun. So I’ll leave it to the many good guys who will gladly point you in the right direction.
If it’s a hunting rig you are building, I can share many years of real world experience hunting different species all over the globe.
It appears that you will be using this rifle almost exclusively, so I would stay away from the extremes. Don’t build a 5 1/2 lb rifle, or a 12pounder. Build something that is light enough to carry but heavy enough to curtail recoil and is easier to balance and shoot.
The .308 is classic caliber, but I have to agree with the other comments about the many alternatives that would be far more efficient.
Again, the caliber is dependent on the quarry, but a super efficient 6.5mm would be one option. If you are totally committed to your current action, it does limit things a bit. I use a .280AI for everything In NA, except the big bears....but it’s a long action.
You can go several directions with the barrel, but I would steer clear of the extreme ends of the options. Hart makes a great barrel, as do a dozen others. You can almost always find a solid discount on this site for a new barrel.
The optics is where I have the strongest opinion. I’m an optics junky and have grown to think of my optics as the most important piece of the puzzle.
My motto is “buy the best glass you can afford, but try really hard to afford the best”.....and from owning almost every top end scope made and having a family member who worked in the industry as an optics engineer, then chief tech/dev officer for two optics companies in Germany and the U.S., I can say that the European glass will be my choice every time. The glass coming from the Pacific Rim is made with a different mindset on the part of the company. I won’t bore you, but i try to see as much about the manufacturer and the process as how things look sitting behind the product.
I run 2 S&Bs (the Exos and Polar), Swaro (currently only the Z8i), and a Leica Magnus.
And before you get sticker shock from the price, I’ll tell you that I bought all 4 as demos for around 75-80% of retail. A used top shelf scope is a far better option than a new one that’s inferior in many ways. Great glass does not wear out....ever.
I will give a shout out to NF, as their scopes are built as solid as any in the world. I owned an Atacr, and the glass was a 9.5/10, with the durability a 10/10. I sold it only b/c it was too heavy. Replaced it with a S&B Exos 3-21x50.....saved 10 ounces and the glass is just as impressive, if not a smidge better.
Also, for a light weight longer range scope with some tactical feel, the March 2.5-25x52 is hard to beat as a complete package.
I have not found more crisp, clear, bright and vivid glass than what’s in the Swaro Z8i......but it doesn’t have the design appeal of the March, NF or S&B (Exos or Polar).
I would choose a reticle that suits your eye and your needs and then back into a brand of scope. I prefer a simple duplex with lighted center dot. I dial my yardage, so I do not need hashmarks. But a reliable well built turret is a must.
Swaro, Leica, S&B, NF, March (even though they are not made in Europe) are all great choices.....Meopta is a fantastic company that is committed to making fine optics at a good price point.
On a typical hunting trip I’m spending an awful lot of time behind a scope or binocs....so I think of my scope just like I do a doctor or a lawyer. When the moment comes that I need to use one, I want the best available.
Boy I didn’t mean to blabber for so long, but it happened. Good luck and have fun with whatever you build.