Very Early Costa Mesa AR-18 Pt3

Interesting things in this picture for sure. Lets start with what looks normal. the bolt, cam pin, firing pin and spring. That’s about it. Straight charging handle, shown here upside down. Similar to the AR180B but those are solid on the underside. Bolt carrier, a lightening cut out is full length as opposed to the partial cutout on the first 1000 Howa’s. Those were expected and had been seen before on other pictures like those of serial number X01. What wasn’t expected was the firing pin retainer. It has a split end not unlike the early solid version in the Colt 601.

A wider shot shows the guide rod assembly. These did not feature a latch as I believe it was found during testing that the rear plate would bounce when struck by the bolt carrier and unlock the upper from the lower. Not the kind of thing you want to happen in a fire fight.

What else do you see? Let me know in the comments and please share these articles with your friends.

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?