Tcao,
I'm not sure, I beleive it depends on what your purpose is?
I don't reccomend the teflon finishes like T on any carbine that will be fired extensively or in long rapid fire strings as it will and does "cook off". I've actually had this happen to me twice, once on an MP5 issue gun that had been refinished in Balck T and the second time on my Wilson M4 with Armor Coat. The M4 cooked off during a carbine course I was taking, it was pretty ugly, the stuff began to blister, then fell off in large chunks. I had it refinished and sold it off, with a warning to the buyer.