AR-308 Part 4

Previous posts in the series:
Part 1
Part 2
Part 3

So, we’ve got all the parts for the basic rifle, now we just need to put it together.

I’m not going to go through the whole assembly process as it’s no different than the standard AR-15 assembly I’ve covered that at least twice here on this blog; also, you can find the process everywhere on the internet and youtube.

What I do want to talk about, however, are the oddities I discovered while assembling. This is related to the weird configuration of the Diamondback lower. As I mentioned in previous posts in the series, the Diamondback DB-10 upper receiver was configured to take DPMS parts, so I assumed I needed DPMS parts for the lower as well. Silly me.

The first clue that something strange was going on was the magazine release. I installed the spring and release, started screwing the button onto the shaft, pressed the button and screwed the shaft into the button until the top of the shaft was flush with the face of the button, released it and…the button wasn’t seated in the receiver. Hmm. Looked like the shaft just wasn’t screwed in far enough.

I pushed the button back in (after lining it up with the hole in the receiver) and screwed the shaft in as far as I could get it to go. that did the trick, the mag release fit now and seemed to operate just fine, but the shaft was sticking out past the face of the button by about 1/8″. It was painful to press the magazine release because the protruding shaft would dig into my finger.

Long story short, I ended up using my dremel tool to cut the extra 1/8″ off of the shaft.

The next thing that hinted something wasn’t right was the bolt catch pin. On AR-15’s and Armalite AR-10’s, the bolt catch is held in place with a roll pin. In my DPMS lower parts kit, the bolt catch pin was threaded on the end. Hmm. Can’t screw a threaded pin into a receiver without a threaded receptacle.

I dug into my spare parts bin and used a standard AR-15 roll pin to install the bolt catch. It seemed to fit fine.

Everything else went uneventfully…but after it was all together, the bolt catch wouldn’t catch the bolt.

After getting a magazine and trying it, the bolt would lock open on an empty magazine, but no matter what I tried or how I manipulated the bolt catch, I could not get the bolt to lock back without a magazine inserted.

In trying to figure this out, I e-mailed Diamondback and explained my issue. They replied very quickly, but told me that a DPMS parts kit should work.

I did some more research and ended up stumbling across a comment from a person who said they used an Armalite A series LPK with their Diamondback DB-10 lower and it worked fine.

I decided to take a chance and ordered a bolt catch from Armalite for $23. It took a week or so to get it, but after installing the Armalite catch, everything worked as it should. I’m guessing that had I also purchased an Armalite magazine release and Armalite takedown/pivot pins, they would have worked as well.

At any rate, with a little trial and error, it went together.

So, if by some chance you ever purchase a Diamondback DB-10 upper and lower set, just know that the upper takes DPMS parts and the lower takes Armalite A series parts…just to keep things interesting.

Still some finishing touches…more to come…

Next post in the series.

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