Q: Is there a barrel contour (octagon, fluted etc) that affords better accuracy? Is there an action type (front
locking, rear locking, dual-lug, triple-lug, multiple-lug etc) that offers an accuracy advantage? Does a Controlled-round bolt (Mauser-type) deliver better accuracy than a push feed bolt with recessed bolt-face.
A: The external configuration of a light to medium weight barrel might have some slight effect upon heat dissipation and this could affect accuracy, but only during a string of repeated shots, and moreso on a hot day. The thickness of the barrel will have more effect upon accuracy than its contour. The size of the locking lugs on the bolt is not a factor, but their location is. Lugs that lock at the rear tend to allow a slight flexing of the bolt with corresponding micromanagement of the cartridge in the chamber, making full length resizing necessary with corresponding shortened case life. A controlled-round feed bolt could be an accuracy factor because it aligns the round more centrally for its travel into the chamber, and hence is less likely to damage the tip of the bullet.