Very Early Costa Mesa AR-18 Pt 2

Lets look at the more interesting side of AR-18 serial number 057.

There are early features everywhere over here!

Of course like the other side you see no reinforcement at the front of the mag well. The most obvious difference is the lack of a dust cover. Early testing showed that there was just too much space for dirt and debris to get into the action. This was fixed during later production.

No curved charging handle on these early models, just like the AR-16 that proceeded it. To my understanding the spent cases would sometimes hit the charging handle and bounce back into the ejection port. To remedy this they changed the design to act somewhat like a shell deflector.

Reminds me a lot of the AR180B.

Other features that may not be so obvious, the reinforcing ribs in the upper extend all the way to the rear. They stop short on regular production models.

Finally we move onto the lower receiver. Compare the front of the trigger guard to the one in your gun safe.

(What do you mean you don’t have one?) (Go get one.) (You know you want to.)

On regular production models the front of the trigger guard serves double duty as a guide for the rear of the magazine. Not so on this example.

Let me know what you see that is different. There is at least one more thing that can be seen in the above photo. Can you spot it?

Very Early Costa Mesa AR-18

Friend of the site Andrew Huber had the opportunity to look over more than a few weapons at the West Point museum and one of them is a very early example of the AR-18. Serial number 057.

Lets look over a few of his pictures and compare those to later production examples.

The most notable feature from this angle is actually what it is missing, the reinforcement around the front of the mag-well. While not as strong I think it has a sleeker look to it. Next would be the roll marks. They certainly made a few changes when they went into production. Unlike the first prototype that is shown in early literature this example uses the traditional folding stock retention stud. Like the first prototype this one does not have a dovetail scope mount on the upper receiver.

It also features an inspection mark on the upper that I have never seen before.

Do you see any other interesting details that I missed?

Make sure you respond, share and subscribe. I’ll dig into the other side of the receiver in the next article so stay tuned. Awesome stuff and I can’t thank Andrew enough for doing the hard work gathering these pictures?

PayPal Killed My Shopping Cart

I knew it would happen some time or another but was hoping to fly under the radar for awhile longer. Worst part is they are sitting on my money for 180 days.


For now I will have to do things old school. Email me with what you want and I will let you know if its in-stock and where to mail the funds.