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Switching to 300 Blackout with The Dolos QD

In case you didn’t see, we covered just how alike your average AR 15 upper and 300 Blackout upper really are (if you didn’t, read about it here). In short, you can turn your standard .223 or 5.56 AR 15 into a 300 Blackout gun with any length barrel (as long as you pay the $200 tax stamp for an SBR if you’re going less than 16”) in just a few seconds. No other rifle affords this kind of versatility today, and we find the interchangeability a huge reason to invest in an AR 15.

If you’re not sure why this is so beneficial, we cover it here. If you can appreciate just how wonderfully innovative this cartridge is, good for you! Let’s go over how you can swap your AR 15’s current barrel assembly and gas system for a 300 Blackout barrel assembly, giving you two rifles in one.

The Dolos Quick Detach Barrel System

The Dolos Quick Detach Barrel System, or simply Dolos QD, is an amazing refreshment to the greater AR 15 market, and it makes a perfect addition to your existing black rifle, whether you’re chambered for .223/5.56, or 300 Blackout.

In short, the Dolos QD allows you to swap your complete barrel assembly and chamber for a different one. No tools are needed, no bench work or gunsmithing is required, and you won’t have to fidget around with that archaic, stubborn delta ring or armorer’s wrench.

How the Dolos QD Works

The Dolos QD is compatible with any standard AR 15 upper and lower. The Dolos QD uses a simple ratcheting mechanism, called a tri-lug, that allows one to screw and unscrew your barrel and handguard as one piece, locking it and separating it from the upper receiver as needed. The tri-lug is placed into the chamber area of the upper receiver itself, where the barrel meets the receiver.

On the back of the tri-lug are three set screws to secure it to the upper receiver with the provided castle nut. Once the tri-lug and castle are installed, a lock collar is placed on the handguard and barrel itself. The two pieces are mated together and twisted to secure the barrel, chamber, and handguard to the upper receiver.

The lock collar and tri-lug both feature lined up holes that your gas system’s tube will feed through. The whole system is so simple and intuitive that removal and reattachment of your barrel assembly takes less than 5-seconds. Installing the entire Dolos QD system to your rifle, SBR, or pistol only takes 10-to-15 minutes.

300 Blackout Compatibility

Because the Dolos QD System is compatible with any standard AR 15, it’s also compatible with every single 300 blackout barrel, chamber, gas system, and upper receiver! This makes the Dolos QD the perfect way to swap between a full-length 16” 300 Blackout barrel and a shortened barrel, maximizing the dual functionality this whisper round offers.

This also makes the Dolos QD the perfect way to truly own two guns in one. Again, because 300 Blackout parts are completely compatible with all standard AR 15 uppers and lowers, you can enjoy switching from .223 or 5.56 to 300 Blackout and back as often and as quickly as you see fit.

The included 11.5” Keymod handguard provides an easy way to retain your favorite accessories on your barrel assembly, and the Dolos QD retaining system itself is compatible with any other handguard that features the same attaching jam nut.


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