Browning makes a good gun, however I think the A bolts are over priced. I like the 60 degree bolt throw they have, but I prefer the Rugers over the Brownings. The Tikkas are good guns also, probably a better gun for the money, they are cheaper then the Brownings. As for the calibers you listed I would go with the 30-06. It is the most versatile caliber on the market, you can get factory ammo from 55gr to 220gr and ammo is found in every little gun shop from the east coast to the west coast. If you reload the choices are endless the 30 caliber has the largest bullet selection on the market. The .308 is a great choice but its only advantage over the 30-06 is a short action. The 7mm mag is a great flat shooting gun very versatile an has a large bullet variety also. I personally don't care for the .270, it is a great caliber but anything it will do the 30-06 will do better. As far as reloading goes the variety is very small compared to the 7mms and 30 calibers and you are limited to lower weight bullets.

That’s my opinion.

Good luck