Nice looking gun!
I've got a Colt CR6724CA that has the same or a very similiar upper. Mine has a 1-9" twist. I added a PRS stock and a 3 pound Timney trigger, so it is very similiar to yours, down to the hand guard and gas block!
The round count just broke 200, so I haven't gotten into any serious load development yet. I did spend a few hours last week shooting some five shot groups at 100 yards, using a Nikon Monarch 5-20, a Caldwell front rest, and a rabbit ear bag in the rear. My eyesight is not that good. My skills, well, I don't know if it is accurate to call them "skills".
Fifteen 60 grain Sierra Varminter Hollow Points yielded groups measuring 0.90, 0.90, and 0.80 for an average of 0.87. Groups had vertical stringing.
Ten 63 grain Sierra Varminter semi-points yielded groups measuring 0.75 and 0.60 for an average of 0.68. Groups had slight vertical stringing.
Fifteen 69 grain Sierra MatchKing HPBTs yielded three groups measuring 1.45, 1.00, and 1.20 for an average of 1.22. Groups had slight vertical stringing.
I need to do a lot more work with this gun, the loads, and with my AR technique, but I'm beginning to suspect that my barrel doesn't like the 69 grain bullets. I would be interested in hearing how your rifle reacts to different bullet weights.