AR-15 Dissipator Style Carbine – 16″ HBAR 5.56 NATO

A custom interpretation by Charlies Custom Clones – HBAR

If you are not up on your “guns of Vietnam,” you may not be familiar with the Colt Model 605. The original AR-15 “Dissipator” as it would later be called, was made by cutting M16 rifles down to 15″ barrels to make them shorter and handier. The issue that came up with this the dramatically reduced dwell time, the time from when the bullet passed the gas port to when it clears the barrel. By reducing this length, the pressurized operating window shrinks, decreasing reliability. Units testing the 605 in Vietnam would often counter this effect through the use of silencers.

We asked our friends at Potomac Armory to make a modernized variant and to resolve the “dwell time” issues of the original 20″ cut downs. Here is the result of their effort.

This unique build starts with the barrel. To understand why, to avoid the “dwell time” issue of the rifle length gas system, we wanted a barrel with a carbine length gas system. Not too hard, right? However, the Dissipator is based on a rifle length gas system, and we still needed to mount the FSB for the front sight and the handguard mount. So now, we needed to find a Carbine length barrel that still had a gas block diameter (0.750″) at the rifle length position. We found a DSC HBAR 16″ barrel that met our needs. A low profile Mk12 gas block has been mounted at the carbine gas port and a Colt FSB has been mounted where the rifle length gas port would have been. The FSB does not serve as a functioning gas block on this gun.

Highlights

• Action: Direct Impingement Semi-Auto
• Barrel: Mil-Spec 4140 Phosphated barrel from Double Star (DSC) 16″ HBAR Carbine, 5.56 NATO, 1-9 twist, 1/2X28 threads
• Carbine length gas with Mk12 low profile (functional) gas block and (nonfunctional) Colt A2 Front Sight Base
• Colt Cage Code Upper Receiver: Matte Black White T-marks, Hard Coat Anodized
• Features Magpul Rifle Length MOE Handguard.
• Colt M4 Carbine marked lower receiver – laser engraved “M4 Carbine”
• Colt factory installed lower parts, including Colt trigger
• Colt 4-postion buffer tube
• Safety: Colt reversible Safety Selector
• Colt factory bolt carrier group
• Sights: MagPul MBUS Rear, A2 FSB Front
• Stock: Magpul CTR Collapsible
• Capacity: 30-Round
• Finish: Matte Black
• Magazine: 30-Round MagPul PMAG*
• Weight: 7 lbs.
• Rate of Twist: 1:9
• Chamber: 5.56 NATO
• Overall Length: 32.5″ to 36″
• Ships in manufacturer’s box with same serial number

* residents of magazine restricted states will receive no magazine

Manufacturer’s Part of the base gun (before barrel mods): LE6920-OEM1

For more on the Dissipator, read the  Blog on the Dissipator

Sandboxx has an excellent article on the history of the underappreciated Colt 605.

Buying and shipping through Charlie’s is easy, but there is some information you need to know. This item must ship to FFL holder. No civilian exceptions.

       1)  Check your state laws to make sure the federally regulated item you want to purchase is legal in your state.

       2)  Find your FFL… Have your dealer send us a copy of their FFL to Charlie’s (Make them earn their fee!!!)

       3)  Be patient! You should hear from our compliance department within 3-4 business days. If not, feel free to reach out for a status updates

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California residents, please see the CA Compliance service.  You should purchase this as one order and the rifle as a separate order.

NOTE: The free shipping option does not apply to full rifles