newer version kit w/lathe-turned guide rod/spring.
AAC rate reducer standard buffer. (not any of the ones that require a special spring)
this is a full-auto kit, in a Colt brand model 614 RR. Full stock.
shorty upper, 5 1/2" bbl.
bbl is 22lr chambered, doesn't use the chamber insert from the ciener kit.
has run ok full mag dump a few times.
runs fine in semi. does mostly double taps in full-auto, very infrequently 4-10rds full. tried CCI mini mags, Stingers,Dynapoints. shoots double taps better with Dynapoints than anything else.
most common symptom: insert mag, chamber round,set selector to full,fire, shoots 2rds and stops. live round in chamber. hammer forward. cycle by hand, fire, get 2rds and stops, same as before.
  suggestions?

I have spent probably a hundred hours on my Ceiner kit to stop exactly what you are getting. You either have bolt bounce causing light primer hits, or the bolt is not blowing back far enough for the hammer to engage the full auto sear.

Buy the most powerful 22lr ammo you can find. Also cutting the bottom of the sear off a bit or the tail of the hammer hook off a bit so the sear will engage earlier might help. A lighter hammer spring might help. Smoothing all surfaces that rum will help the bolt blow back.

Cutting the main spring has worked for some, but I find the problem you describe is often caused by ammo not chambered tight enough and sealing good, causing weak recoil.

Good luck, it's a project for your lifetime. I am giving up on mine and selling, as the 22lr kit in my UZI works so well that the M16 has become not worth the effort.

You didn't mention it, but I'm assuming you are using the anti-bounce bolt weight supplied with the kit.  My kit had those same symptoms, but not as frequent.  Using the advice of others, I bought a few recoil springs from [url]http://www.lakesideguns.com/[/url].  The Ciener supplied recoil spring was a little weak and wouldn't even strip the first couple of rounds on a fully loaded 30 round mag.  The Lakeside Guns springs are much stronger. Once I trimmed several coils off the spring, my problem went away entirely.  I'm not sure, but I think the stronger spring helps to prevent bolt bounce.  Or maybe the spring keeps it in battery with greater force?  Their recoil springs were about $3.00 each (if I remember right) about six months ago. Maybe this will solve your problem?

Edited to add the following:

Before I cut the recoil spring, I did two things: (1) I adjusted the hammer spring.  By bending the hammer spring I was able to reduce the spring tension.  The hammer won't hit as hard, but it doesn't need to when shooting both 22lr and 5.56mm.  (2) I cut one or two coils off the firing pin spring.  I don't understand why the firing pin spring has so much tension?  At the same time, I polished the firing pin so it slides in and out by gravity.  This reduces drag/friction on the firing pin.  

I did these two things so I could maximize recoil spring tension.  With the stronger recoil spring and lighter hammer spring, I can shoot CCI Standard Velocity and CCI Subsonic perfectly until it gets dirty (about half a brick).  I was at a machinegun shoot and one of the guys there couldn't believe how well my M16/22 was shooting.  He told me he had worked on his for multiple hours and could not get it to run consistently.  

Dan

I bought two in my quest for many mags.  One worked 99% and the other worked 70% or less.  The bad one never finished a full mag.  Considering the cash you have in your Colt I would just buy a new kit and try it.  If it doesn't work buy another untill you find one that works.  Sell the ones that don't work on ebay.  Chances are that the guy buying it only wants it for a semi-auto, so it will work for him.  The time people spend on trying to get these things to work is amazing.  Just say no.

Now it works! I did all the polishing, then bent the sear trip at the rear where it's legs sit in the notches. bent it so the legs pointed more forward and the "belly" more to the rear. worked like a champ!
now it runs with an occaisional stovepipe, gonna have to fine tune the mags a bit. thanks to all who helped, I appreciate it!

Ciener's .22 conversion kits for M16's seem to have this problem way to much.  I have had it happen and had to fix it myself.  Dealing with Jonathan is a waste of time.  Product needs more work, but the manufacturer will not take the time to do it right...