I've got an AR10 A4 with a 20 inch Chrome Lined barrel, with my more accurate handloads it averages right around 1inch for 5 shots at 100 yards. Fair accuracy considering that it does not have a freefloated handguard and it does not have a trigger that is condusive to target shooting due to it's heavy pull and creepy movement.
I'm thinking that I'm getting a tad bit of barrel warping as the barrel heats up from shooting a string, to date I've had LOTS of 3 shot groups in the 3/8-1/2 inch area at 100 yards but pushing for 5 shots I always watch the groups open up. One of these days I'm gonna actually sit back and wait between shots to assure that the barrel has time to cool and I'll see if I can't get the groups down there.
I actually wanted a "T" model with 24 inch barrel but at the time I couldn't afford to pay 2200 dollars as opposed to the 1400 I paid for my A4 and I was also in a race with the Ca. legislature in that when I saw an AR10 on the shelf I had to really question when would be the next time I'd have an opportunity to pick up an AR10. Funny thing was that during the 10 day waiting period after signing the paper work the shop got in the exact AR10 model I actually wanted but couldn't afford.
It's okay though, I bought my AR10 with the sole intent of having it reworked and having an additional upper or two in the gun case so that I could have both a rugged hunting/general use upper as well as a few custom built tack driving uppers in real long range chamberings like 260Rem or 7mm08.
Love the Ar10 though, magazines are pretty expensive but the SR25 mags are even more expensive.
Here's a pic of the ugly gal.