Dimecovers3,
There are several top end smiths on this board alone that would do amazing work, Shawn Carlock, Chris Matthews, even myself can built a decent rifle from time to time.
If your going to build a 280 AI I would recommend getting the 40 degree version as it feeds fine, has the most capacity of all the Imp rounds that do not move the shoulder forward and limits case stretching more then the shallower shouldered versions.
The last 280 AI I built was on a Rem 700, H-S Precision Stock and Lilja barrel and the first three, three shot groups out of the rifle averaged barely over .3". That was with virgin brass.
When set up properly the AI rounds will shoot very near if not better then 1/2 moa so they are completely usible in the field even for moderate range varmint hunting.
From what I am seeing you looking at near 3300 fps with the 140 gr pills depending on barrel length which I would recommend 24 to 26 for a sporter rifle, 26 to 28 for a heavy.
The only difference I would see between a Rem 700 and a Ruger #1 would be first and formost cost. Rebarreling a #1 is a far lengther task then a Rem 700.
Accuracy potential would lean hard toward the favor of the Rem 700 as well. Maybe I should say consistancy instead of accuracy.
The 1-9 twist would be perfect for the bullet you want to shoot at any range.
Its a great round and easy to get tight groups in and fully up to 1000 yard shooting if set up properly. Will give factory loaded 7mm Rem Mag ammo a very hard run in performance numbers.
Good Shooting!!
Kirby Allen(50)