I've got access to a nice R700 bolt gun, so thats my reasoning for going with a semi. I'm not planning on shooting any matches with it, so accuracy could be in the 1.5MOA range and be just fine for my purposes. I've fired 5.56 out to 400yds from a service rifle (no upgrades), and it was accurate enough - only problem was, it didn't have enough knock down power at that range, so it sure as fire isn't going to have it at 500-600yds. One factor I didn't mention earlier was the history behind the M1A (AKA M14), so that may play a small role in my decision. I think right now I am between the M1A and a nice AR10 setup. The stated budget of $1000-1400 is just for the rifle, and I know I can get both of those in that price range. The only question is the quality of firearm I will get for that money. If I can get a very good AR10 but only an OK M1A, I may get the AR10. Still not sure though...
What kind of power do you need at longer ranges and for what purpose? If its hunting, I completely understand the 308. If its defense purposes, 5.56 is very adequate when using proper ammunition. There's a guy a number of us know that has a good handful of confirmed kills at roughly 400 meters with a 10.5" mk18 and mk262 ammunition. TSX would likely be even more effective. There's countless confirmed kills at 600 to 800 meters as well using a 14.5" or 18" barrel 5.56.
Don't get me wrong, If all I was doing was long range shooting and needed my target to drop quickly, I'd opt for the 7.62 (I have a SCAR H and 700 and will be picking up an SR25 or MWS in a handful of months). If I was doing a lot of close range shooting, 200 meters and in, with the occasional 500 or 600 meter shot, I'd opt for the 5.56.
I've dropped 2 hogs on the spot at 200 meters with 70gr TSX, one was almost 300 pounds. The problem is that 5.56 is very dependent on ammo election, while 7.62 will be effective with any ammo, of course more effective with higher quality ammo.
I should also state that I'm not opposed to buying a used firearm, of course, as long as its in great shape. Any advice on buying a used M1A or AR10?
I'm not very knowledgable on the M1A or really even the AR10, so I can't point you in the best direction. I'll email a buddy though and see what he has to say and post back if it's relevant. I'd suggest heading over to M4carbine.net and (only after searching though similar threads) post about it in the AR10 subforum.
Here's a link to the subforum and use the orange search feature at the top....