These old guys are doing not talking . I never saw a 1/4MOA AR yet, but it is possible in contolled conditions I guess. A Lilja or Krieger match grade barrel,cyroed and glued into a Stolle Panda action or a blueprinted 700 action with a light benchrest(Varmint) fiberglass stock with a good 8oz trigger(or as low as 2oz) and a lapped mounting 12X or better high grade optic shooting Berger or other Match grade bulletsthat have been straight line micrometer seated off the lands at optimum depth MAY get you 1/4MOA regularly if you spend a couple seasons and many thousand rounds of training. BTW a fluted barrel has more surface area and the exterior angle form buttresses and the process stress relieves the barrel generally. I started getting some barrels fluted in 1983 as Chet Brown and Lee Six , who both lived in San Jose Calif and invented the fiberglass stock(around 1975) started doing it on the custom rifles they built me.It was a trick to get a lighter but stiffer benchrest barrel under the class weight limits.
