WTS: COLT AR-15/M4/M16 Fully Assembled Full Auto Bolt Carrier Group

[Rodney's Distributors]

WTS: COLT AR-15/M4/M16 Fully Assembled Full Auto Bolt Carrier Group

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COLT AR-15/M4/M16 mil-spec standardization objectives by the U.S. Department of Defense. Original COLT fully assembled Full Auto Bolt Carrier Group Complete includes the bolt, bolt carrier, gas key, firing pin, cam pin and firing pin retaining pin. $229 shipped

In 2005 the ATF issued Colt approval to use full auto bolt carriers in any gun that will accept one (excludes the versions with the receiver block simply because it will not physically accept one). 

The ATF gave Colt permission to cease production of the semi auto bolt carrier and use full auto carriers in all of their new production models. Of course...exhausting current stocks of semi-auto carriers first. 

The reasons were explained to our class as follows: 

Problems have been linked for years to the lessened weight of the semi auto bolt carrier and the shape of the rear most portion of all 4 types of semi-auto carriers that have been designed over the years. Tests even proved that although one might not realize it, the rear of the bolt carrier in the half-circle design, actually flexes and vibrates during firing. This, along with the carriers weighing less than was intended in original design has been found to be responsible for a lot of malfuctions and excessive parts wear due to the bolt carrier actually sliding and grinding against the upper receiver and receiver extension when the flexing and vibration occurs. 

Colt was able to articulate and prove that the bolt carrier was not "designed and intended solely and excusively" for full auto use. The same carrier was shipped in original AR-15 semi-autos (which shipped with semi-auto only fire control parts). 

They proved that the AUTO SEAR was designed exclusively to work OFF of the bolt carrier....and NOT the carrier to work off of the sear... 

The bolt carrier was designed in that original form. Stoner realized he needed a component to retard the hammer on its return cycle toward the firing pin to keep it from firing out of battery. So he designed the auto sear AROUND the already existing lower foot of the bolt carrier.....and bingo....there you have it. 

Every single one of you, with 90% certainty(10% for those who actually might have an OLD upper reciever that was made without it) possesses an upper receiver with a sear relief. That sear relief is designed and machined into the receiver "designed and intended solely and excusively" (as the law states) to facilitate the functioning of fully automatic fire. 

The ATF long ago approved the industry use of the exact same upper receiver for semi auto sales as was and is being used for full auto weapons. The same thing has happened with the bolt carriers. Colt quit making separate semi auto only upper receivers and was able to simplify production...just as they are now doing with carriers. But now, the full auto upper receiver is accepted as the industry standard. The bolt carrier issue is just so new that people are still skeptical.

Edited September 3, 2018 by Rodney's Distributors