Just drop in and shoot on mine. Some require a little tweaking but mine didn't. Then mags may need to be tweaked also. I love mine and have put about 1000 rounds thru it. unfortunately, I bought an SC xd9 this year and am having so much fun with it, I don't change out the barrel much any more..
Contact Old School and he can give you the low down or just do a search on EFK on the faorum and you find all you need to know.
Rikoshey :twisted: