Yes there are detailed instructions for building an AR . Torque specs to be followed for a reason most barrel nuts have a range for the torque . I've seen barrel nuts that were just hand tight and they wondered why it wouldn't stay sighted in . True the upper receiver before you start your build use the proper vice blocks and for me I like a clamp on gas block so it doesn't add any stress to the barrel on just one side . As for a chamber I like the Wylde in a 20" barrel running one in 8 or 9 twist and heaver bullets . For deer I'm a fan of 243 and up for bear I think 30 cal. and up something about me being lunch just doesn't set well with me . I don't think I would recommend the 7.62x39 for bear but then the guys up north do go out for polar bears with a 223 each to their own .