Now that the ban is over, I took my newly assembled he  By the way, AR15 rocks.

 1--- UNLOAD the firearm ----

Look in the ejection port, and slowly bring the bolt rearward, while watching for the ejector finger to appear in the groove-face of the bolt.....

Make sure the finger is as tight to the bolt center so it get maximum contact with case (which is not much, so you need all the contact you can get).

Double check extractor roll pin, I assume it (bolt) is COLT, as some have reported use of sub-standard roll pin or incorrectly set, not holding extractor proper. I have Garrison, it is fine.

With upper seperate from the lower, drop a live round in the chamber, and close the bolt. Look and see if the case face is flat to the face of the bolt, if not, may have headspace issue, mine did (custom barrel),, had to do a little lathe work to get it to where I wanted it.

If most of your parts are Colt 9mm then might as well get a Colt mag block and that might solve your problems.

My 9mm is all Colt and I have never had a jam or failure. Shoots all types of ammo I throw in it too.

Thanks to all for your ideas.  I'll try slightly lowering the mag block (it was my first thought as well) to see if it eliminates the feeding probs.  My mags are all factory colts, 3-32s and 1-20, and they appear to have tight springs (I can't load more than 27 rounds in the 32rounders with my bare hands).  With the same feeding problem occuring with all four mags, I gotta rule them out as the culprit.  I hope its just that the block needs adjusting.  Thanks again for all your help.