personally when i when i built my 260 i went with the lug and the nut and the reason being is after removing the factory barrel and seeing how tight the factory put the nuts on and knowing that im going to reinstall the nut at 25ins lbs my thought was the more nut contact the better...now does it matter? maybe not but im a firm believer that the truer a mating surface is the better...if your rebarreling or doing a custom build why use a factory nut that a gorilla tightened? plus you bought a nice barrel and the lug why not the nut to finish it off?...you can get nuts from mcgowen as well that are pretty nice and a little cheaper.