Target shooting at pistol ranges need not have a CMP heavy barrel on an AR15.
There is no difference in accuracy between high quality chrome lined bores (Bushmaster and Colt's) and ordinary non-chrome lined barrels such as sold by RRA and Model1 Sales, etc.
Folks who sell non-lined barrels would like us to believe differently, of course, just like folks who only sell HBAR barrels would like us to somehow believe they're more accurate.
True match barrels are, of course, unlined and heavy. But that confers no special accuracy to all unlined barrels or all heavy barrels. V8s ain't always faster than 4 cylinders, I know of 4 cylinder street machines with 0-60 times in the 4s. Not even a good V8 (or V10) will beat a good 4 every day. Seems as if some folks are buying the "unlined heavy is more accurate" nonsense; there's more to it than that.
Even a M4 length barrel will shoot 1.5" groups off the bench with macth ammo if you do your part.
All barrels are chrome-moly steel, nothing special about that.
Ammo and your shooting will be the major determinate of accuracy at pistol ranges like these. Unless you're using a sling or a bench rest you're not going to get 1.5" groups at 100 yards with any rifle unless you routinely place in the President's Hundred at Camp Perry.
-- Chuck