ICAN, is your ammo M118 white box or M852? the M852 has a knurled ring near the back of the case and the 168 Smkhp, and is very hard to find. The M118 has the old 172 gr full patch bullet. The M852 is better ammo in my opinion. There was also some brown box M118 special ball that had the 172 gr bullet. I never had a M1A that would shoot the special ball, and when I quit match shooting, that was what they were issuing for leg matches, except at Perry. Check the rules if you decide to shoot CMP matches. I think we used to have to lift 4 1/2 lbs on the trigger.
6" at 700 yards is very fine shooting. Sounds like you have a winner. You may actually not like a scope on the rifle. I have had a couple of good rigs on mine (A.R.M.S. and Swan mounts with Leupold, and Tasco Super Sniper), but always ended up taking them off.
Something that may be useful; I never stored an M1A (or N/M Garand) clamped up. It will gradually lose its preload and compress the stock under the bedding. A good one will shoot 1 moa or better when first clamped up, and in 3-5 rounds will be back at its best.
I was acquainted with Glen Nelson, Clint Pyle, and Don Benson. The performance of their rifles prompted me to try it myself, and I was never disappointed. I tried to shoot mouse guns, but never had the confidence in them that I had in the .30 cals. I predict you will get hooked on this rifle.
Sorry I got so long-winded.
I'd like to hear how you like it with the scope. Tom