Re: 243 pros & cons over 308
All things being equal, I'd take the .243 any day of the week. Faster, flatter and flies straighter. The .308 takes a bit more skill to shoot. Not that you don't need skill to shoot the .243 though. You still need to read the wind.
I personally went with a .308 and this was due to a conversation that I had with my builder when I had my first rifle built. I had a .308 action and asked about what calibers were available to me. For my purposes, the choices came down to two. The .243 and .308.
He told me that when he shot .243, his regimen was to replace the barrel every 800 rounds, because at that point, the loss in accuracy was coming due to the throat and rifling beginning to be shot out. With the .308, he said that I should be able to get about 5000 rounds out of the throat, at which point I should be able to just have the barrel set back and rechambered for another 5000 rounds of shooting.
I do think that the 5000 round estimate may have been a bit optimistic, but I'm at just over 3000 right now and it's still shooting in the .2s and .3s at 100 yards. We'll see.
I don't know what barrels you are running, but I like Kriegers. So that means about $500 for a new barrel. I know that the cost of the barrel is a drop in the bucket compared to ammunition costs, but still, I'd prefer not to incur any unnecessary costs.
Besides, I like to shoot F T/R, so .308 is it for me, for now anyway.