i just finished a JT postban 20" A2 build, with no bells and whistles. the kit went together great, and is producing 1/2" groups at 100 yards.
my question is are the JT kits chambered for .223 or 5.56? I have only used .223 so far, and was wondering if 5.56 was safe to use, i can't find a marking anywhere on the upper. thanks.