The Upper Receiver – “Mil-spec” could be wrong for you.

The Upper Receiver - "Mil-spec" could be wrong for you.

 The Upper Receiver - "Mil-spec" could be wrong for you.

The Upper Receiver – “Mil-spec” could be wrong for you.

The Upper Receiver – “Mil-spec” could be wrong for you.

As more and more AR-15s are purchased every year, the number of owners who become proficient and building AR-15s from parts is increasing as well.  It’s nearly impossible to know the number of AR’s built from parts, or to track growth curves.  What we can look at, are the number of parts sold, number of do-it-yourself kits sold, and number of “how to” tutorials popping up seemingly everywhere.

 

As “parts checklists” go, the upper receiver is probably the component that receives the least consideration.  What is there to really think about?  Obviously, you’d decide on billet vs. forged, then possibly a specific manufacturer, and most importantly PRICE.  It seems that last on is usually the deciding factor.  There is another consideration that the majority of shooters never even know they should examine when selecting an upper receiver for their next build.  Specifically, we’re talking about the ejection port.

“Mil-spec” as a term in the civilian AR parts market is only loosely related to the true meaning in the military manufacturing industry.  If you would like to learn more about the difference between mil-spec and commercial AR-15 parts, a great article can be found at http://fulton-armory.com/faqs/AR-FAQs/Mil_Spec.htm that can give you a basic understanding.  More or less, most commercial AR-15’s uppers are CALLED mil-spec, because they are all pretty similar (7075 aluminum forging, anodized black, and fairly standard dimensions).

“Billet” upper receivers are not as identical to each other from one manufacturer to the next.  The term billet implies they are made from a “billet” (solid piece) of aluminum, and were not cast in a forge.  Each billet upper receiver on the market tends to have slightly different design aesthetics from one manufacturer to the next.  Some claim to be stronger, others are lighter, made from rare alloys, …….you get the idea.  What “mil-spec” and “billet” upper receiver tend to have in common, is that most of them have standard size ejection ports; meaning, the same size as a military M16 rifle, and designed for the 5.56 NATO round.

Here’s where you should examine your options.  If you decide to fire larger bore calibers, your upper receiver must have an ENLARGED ejection port.  Larger calibers will not cycle through the smaller ejection ports, as they are too narrow to allow the case to eject.  The AR15 world is changing at a quickening pace.  As some examples, the .450 Bushmaster, .458 SOCOM, and .50 Beowulf are available from many sources (both rifles and ammunition).  Popularity has increased with cartridges that most had never heard about 10 years ago.  Where will we be in the next 2 years?  It makes sense that if you ever foresee yourself trying out a larger caliber, that your upper receiver already has an enlarged port.  In most cases, the price difference between a standard upper receiver, and an enlarged ejection port upper receiver is less than $20.  That $20 now could save you from buying a whole new upper receiver later (at which time you’d be spending the extra $20).

If you’re interested in shooting larger calibers, you might consider learning more about the War Lock Complete Upper Receiver.  The War Lock allows the AR-15 owner to quickly change through 60+ calibers, without the need to purchase additional upper receivers.  Use the same upper receiver, which means you don’t need an optic for each individual caliber that you want to shoot.  Retrofit your AR-15 one time, and simply change barrels, bolts and magazines (typically) for the dozens of possible calibers, all through the rifle you probably already own.  Each upper receiver we sell comes with an enlarged ejection port, so that you’re able to shoot the larger calibers right from the very beginning.

The Upper Receiver – “Mil-spec” could be wrong for you.