Lash,
There is nothing wrong with shooting a .30-06 in competition. There's a fellow by the name of German Salazaar, a world champion that competes with a 30-06 and is a foremost expert on shooting the 06. His website is here
The Rifleman's Journal: Articles Index
The barrel should be chambered with a serengetti reamer as recommended by Mr Salazaar.
The only con about shooting an 30-06 to its potential is recoil. If the 30-06 is to be shot at 1,000yards, then you want to load it to the same pressure levels as a 308, which means, you'll be effectively shooting factory 300WM ammo. It is a lot of recoil to contend with, especially in any sort of bullseye competition where muzzle brakes are not allowed.
If muzzle breaks or cans are allowed where your buddy shoots, then the above caution is moot.
If muzzle devices are not allowed, the best bet to alleviate recoil is to do one or combination of the following:
1. download the ammo to slightly faster (~100fps or so) over 308 velocities
2. modify the rifle stock to add a recoil absorber
GRACOIL ADJUSTABLE LENGTH OF PULL RECOIL REDUCER | Brownells
3. Ensure rifle weight is high...say 18-20lbs or upper end of competition limit.
Thus far, I've been shooting an M1 garand in highpower competition (iron sights @ 200yards, 300yards & 600yards) and have dabbled a little at 1,000 yards...I gave up on the garand at 1,000 since the rear peep sight is elevated so high that you no longer have a cheek-weld, and also, there are better tools for the job. The loads i shoot out of my garand are bolt gun loads...and because i shoot them out of a semi, recoil is only a little bit more than on my 308AR. I am able to get away with it by using a ported gas plug. Specifically this one
Shooting Commercial Ammunition in your M1 Garand
I just picked up a bolt rifle in 30-06 that will be my dedicated 1,000yard gun. It is a Savage Model 110 BVSS with a laminated stock and 26" fluted Varmint barrel and accutrigger. Picked up this rifle for $630 off gunbroker. These rifles frequently pop-up on GB and gunsamerica, so if you are patient, these can be picked up for a song.
Building a rifle off an Remington 700 action would be easier given availability of components.
All that said, how good is your buddy at wind reading? Because to be honest, what separates the top shooters from everyone else is one's ability to read the wind and adjust accordingly. The rifle, action, caliber, etc are all secondary to this...they provide an advantage only to shooters (< 1% of shooters) good enough to be able to shoot the difference...
