My father-in-law shoots competitively, with the International Benchrest Shooters. My $0.02 says figure out what competition you'd like to shoot, and build accordingly.

 

not to sure about the availiblity of the 416 but saw it action once and it was pretty kool

 

jc,
When you say jump in head first I hope you have real deep pockets.
For long range accuracy the BC of the bullet you are using is probibly the most critical single thing. Velosity is the second thing you want to look at when considering the round to go with.
Now the gun, if your wanting first class your going to put over $ 2,000 in the gun. The scope will be another $ 1,000 plus. I just built a long range coyote gun, a .22-6mm, on a Savage action and have over $ 1,000 in it and another $ 1,000 plus in the scope on it, and while it will shoot with some of the better guns out there, they still have enough of an edge I don`t stand much of a chance against them.
One very big thing is safty. If you do not have experance with wildcats you will need help with working up your loads from someone who does.

 

There aren't many competition venues that will allow you to compete with that cartridge (Sniper Challenge), and the 408 CheyTac is the king of that class of long range shooting due to it's accuracy. It shot sub MOA at 1,600 yards at White Sands during the initail range testing done during the developement of that weapons system. In the beginning there were quite a few knowlegable individuals that cried foul, or maintained that the accuracy and ballistic data was BS, but all have since ammended their position.

Decide what classification, or type of long range competition you want to compete in, and then have a rifle built that will conform to the rules governing that class of competition.

My suggestion would be to start in F Class. It is becoming to the long range shooting competition world what Bracket Racing has become to the world of Drag Racing - a way for the average Joe to compete in long range competition. It is sort of a "run what you brung" type of venue, and you can compete with your hunting rifle if you so choose.