Well, if you want tackdriver accuracy, you need stability. You don't any little model Seven's or other lightweight guns, you want some extra weight. I'd say 8.5 lbs should be your target weight for your rifle once it has a good variable power scope mounted on it. A 7mm-08 or 308 either/or would make an excellent caliber choice, moderate recoil, good energy,speed, and trajectory. Also, try out different ammo, and if handload, try different loads and bullets in your rifle to find the one that is most accurate. Test from natural hunting positions.

I've got a Stainless A-bolt in 260. It handles and shoots great. I think it may have an accuracy edge over the Ruger. I own a Ruger MKII in .280, and I like it too, but the Browning gets the edge. Mine's stainless, so it's a little heavier. The hunter and medallion models are lighter, as is the composite stalker. The shorter bolt throw is nice, and the bolt is smoother. Go pick one up and see how it feels. The Browning also can have the BOSS on it, which can make it even more accurate. You'll be pleased with the quality Browning puts into their guns. My experiences with Browning (BLR, two A-Bolts, BAR) have all been very good. You won't be disappointed.