Not as difficult as I thought it would be. The only problems that stood out was deciphering which springs go where. The diagram provided by DD wasn't exactly the most detailed. I had to use one of the detent springs from the DD lower kit when I lost one from my Plum Crazy that I sold. I ordered a replacement from Midway. A little voice told me to order extras. Glad I did. Bent the heck out of the rear detent spring when putting the buffer tube on. I'm not confident I got the castle nut tight. The wrench I have had problems getting around the sling swivel.