Rocklobster,
Why??? For one thing.. $$$$
Garands are $500 from CMP. This gets a guy into the highpower game at the entry level. After he wears out the original '06 barrel (or if it is already close to gone when he gets it) he can send it to Champions Choice and for less than $200 he gets his rifle back with a Match Grade Douglas .308 barrel installed and ready to go. Total investment, $700, for a rifle that is, in all probablility, more accurate than it was originally.
The M1-A starting price is at about $1200 and this does not even come with the Match Grade Douglas barrel. Not until you reach the National Match model at around $1700 or so do you get it, and let's not even go to the Super Match M1-A model at $2200+. That's a fair chunk of change for the average Joe to shell out when he's just beginning a new sport. The Garand looks a lot more attractive at that point.
FYI, I own an M1-A with the Douglas Match Grade barrel. Shoots pretty good. I bought it before I acquired my first Garand. Had I bought a Garand first, it is doubtful I ever would have spent the money I did on the M1-A.
One thing that is purely subjective for me is that the Garand BALANCES so much better in standing than does the M1-A. No matter how hard I try, I can't beat my M1 standing scores with the M1-A, even though it is proven more accurate from it's bench and prone scores. The difference is so pronounced that my aggregate with the M1 beats my scores with the M1-A, even though it is obvoiosly the more accurate rifle.
For any reason other than $$$, ask the thousands and thousands of guys who HAVE done the .308 conversion on the M1 over the last 40+ years why they did it. Go to any NRA highpower match and look for the guys shooting M1's. You'll find just as many in .308 as in '06. There must be some reason for that... I think it goes back to the reasons I stated earlier:
Better accuracy
Slightly less recoil (less powder, lower ejecta)
Better accuracy
More available match grade ammo
Better accuracy
When you shoot highpower rifle competion, you shoot a LOT of rounds. Barrels wear out over time. If it's time to replace a worn out barrel anyway, why not put on one with the above advantages???? Makes plenty of sense to me.
Swampy