I checked the articles and didn;t find what I was looking for. Regarding ARs, can someone describe the what Blue or Green lable means? What fenced is? and the difference between forged and un-forged lowers? Is there a glossery of terms?

Thanks

Green label:  Colt, earlier, more desireable, no sear block, standard sized fire control parts pins.  Blue label:  Colt, later, still preban, but with a sear block and larger fire control parts pins.

"Fenced" refers to the raised area on the lower receiver under the ejection port and around the mag release button.  Later rifles are fenced, earlier ones are not.

Forged lowers are generally considered better (sronger, nicer looking) than cast.

Green label refers to Colts AR-15's that among other things came in a box with a "green label". These are pre ban and they have a bayonet lug and flash suppressor as well as standard size pins on the fire control parts. The blue labels came in a box with a "blue label" these are more recent manufacture and some are pre ban. They have flash suppressors though I've never seen one with a bayonet lug. The pins for the fire control parts are larger than standard. There are also post ban blue labels as I believe Colt still uses the blue label on current production. A fence refers to the ridge around the mag release button that is part of the lower receiver forging. It was added to the design back in the 60's(for the military) to prevent the mag from being released by an inadvertant bump. Forged receivers are made by putting maliable aluminum in a die and dropping a weight on it(hammer forge) creating tremendous pressure resulting in a part that is in the general shape of a lower receiver. It is then finish machined. Forgings are considered stronger than castings. Castings are made by pouring molten aluminum into a mold the shape of the receiver. It is then finish machined. The difference in strength has to do with the grain created in the metal during the forging/casting process. The best way to tell the difference is the markings. A casting will have raised lettering a forging will have stamped lettering. If you find one with no markings, you're on your own. Incidently, I've never seen a forged upper so I'm not really sure if there is a big difference in strength since castings have been working fine for upper receivers. No glossery of terms on this board as far as I know.

Thanks! Great board! I've learned a ton of helpful stuff here.
Larry