Got my AR all put together and took it out to try it today. It would shoot but the carrier would only slide about half way back and stop. I figured it was because there was not enough gas pressure. I took off the block, double check the alignment and checked to see if I could blow through the gas tube. It all checked out. The key seems to slide easily over the tube too. Out of ten shots, it only jacked out the shell once. A couple times the carrier did not move back at all! Any input on what the problem could be? I think somehow the carrier is binding up, but when i use the charging handle I can cycle a whole clip very easily, but when it fires it will not. THANKS

It was not a kit, it was a DPMS barrel Hbar, a RRA flat-top upper. Wondering if it is the headspace?

Headspace has nothing to do with this problem.

First, check the carrier key. Make sure it is tight and the screws are staked. Next, check for gas blow by at the gas port.

For the next check, make sure the rifle is UNLOADED. Cycle the action and pull the trigger. Continue holding back the trigger and with your other hand pull back the charging handle to cock the hammer again. Release the trigger and you should hear a click and the trigger should move forward. The hammer should be cocked and with another trigger pull the hammer should fall. If the hammer follows the carrier down or the hammer binds the carrier, you have an unsafe rifle. Most likely it is the disconnect, but at the very least you have a bad trigger. Get it replaced or repaired. Firing as it is is unsafe and a slam fire or going full auto can result.

No, what will happen is that if the disconnect is faulty or the hammer is faulty, it will bind the carrier when the carrier tries to go back forward. When the carrier comes back this is what cocks the hammer. The disconnect should then "hold" the hammer back (cocking it) and it will not release again until the trigger is pulled. This safety check works with all AR triggers both single and two stage.

Ok. let me get this straight...
1. unload the gun
2. pull back the charging handle and release it.
3. pull the trigger so the gun dry fires.
4. continue to hold in the trigger and charge the action again
5. let off on the trigger and it should move forward and there should be a click?

I did that and sometimes it would click and move and sometimes it wouldn't???? I kept doing it and now it seems to move forward and click everytime. If it didn't click how would this keep the bolt carrier from sliding all the way back and not ejecting the shell? Guess I am a little confused here. THANKS!

Not ejecting the spent case makes me think it's a gas leak problem.

Sounds odd I know but chamber an empty case and blow into the muzzle.  You should feel very little or no gas leaks.  

Check the bolts on the carrier key.  Some have reported broken screws with the head held in place by the staking.  

If the carrier is binding up when you release it, it is a defective hammer or disconnect or both. If the trigger does not reset itself and follows the carrier when it goes forward, it is a defective disconnect. This is just one problem it might be.

What type of ammo are you shooting? Factory, mil surp, reloads, what? If reloads it could be that you are not sizing the brass properly. That is a very common problem. If mil surp, some of the mil surp out there is known for functioning problems, the Greek for one.

The carrier seems pretty smooth when pulling the charger back. I can manually load and unload a whole magazine no problem, but when I fire it, the carrier only goes back to about the point where the bolt head is right in the middle of the ejection port. I am shooting factory ammo. Tried some Black Hills and some Ultramax, same results with both.

Other areas to look at:

Carrier key, see if it is loose.

Gas rings, see if they are worn out.

Chamber, see if it is rough, pitted, dirty, etc.

Gas blow by at the gas port, look for staining on the barrel where the port is.