I have a few used barrels that came from full auto's and am trying to get an idea of wear in terms of rifling etc. Are there any signs to look for to determine the condition and amount of use? I have examined the rifling of several barrels but to my untrained eye they look sharp. I guess the definition of "sharp" is what I am looking for. Also signs of wear at other areas....trunion etc.? Any help is appreciated. Thanks.