The New Frontier Armory 8oz Blowback Buffers are specifically designed for 9mm AR pistol caliber carbines. They are longer and heaver to meet the increased recoil impulse and shorter stroke of direct blow back ARs.
Conventional ARs use a direct impingement AR to cycle the weapon. This blows gas through a tube to cycle the bolt. The bolt is locked into place while firing. Pistol Caliber AR’s (9mm, .40, .357 Sig, .45, etc) use Blowback Operation.
With a Blowback system the bolt doesn’t lock. The only thing slowing down the action is the combined masses of the bolt and buffer along with the resistance of the spring. If there is not enough mass, there is more felt recoil that can break parts and crack receivers. With Blowback ARs there is no Gas Block to adjust so your only option for tuning is to adjust the buffer weight.
Made in America, the Extra Heavy 8-ounce Blowback Buffer from New Frontier Armory is the perfect tool for taming direct blowback.
Features
- EXTENDED LENGTH FOR PROPER BOLT CATCH OVER TRAVEL
- WORKS WITH STANDARD CARBINE SPRING
- 10 OZ BUFFER WEIGHT
- FOR BLOWBACK OPERATED BUILDS ONLY
One warm summer night in 1981, Marine and genius firearms designer Maxwell Atchisson was drinking a Coors beer, listening to “Hit Me With Your Best Shot” by Pat Benatar thinking about the XM177E1. (How many times have you ever seen Marine and genius in the same sentence?)
While the XM177’s CDI factor (Chicks Dig It) was off the charts, it wasted a lot of energy as flash and noise. It got very dirty quickly and the ballistics on the 10.5 inch barrel left a lot to be desired. As the song changed to “Free Bird” he realized that the XM177 needed to be redesigned in 9mm. (Warning: This historical reenactment may not be completely accurate.)
He was a genius and could just do stuff like that. His 9mm gun was a closed-bolt, simple blowback-operated submachine gun.The simplicity of blowback guns has always interested me. Since most of these designs are full auto, most shooters don’t encounter them. Atchisson’s blowback system consisted of a heavy bolt resting against the base of the 9mm cartridge case, and a heavy buffer and recoil spring that is compressed by the kinetic energy of the bolt when it is thrown back in recoil.The stored energy of the compressed spring drives the bolt forward into the firing position.
This eliminates the whole gas system, allowing the use of very short barrels. For close quarters, it had all the energy it needed in a small, low-recoil package with the great ergonomics of the M-16. A 10.5-inch barrel is the sweet spot for 9mm, giving near optimum energy.Colt’s lead designer, Henry Tatro, took over the project and in 1985, Colt introduced the 9mm SMG.
Colt was more interested in parts commonality with the M-16 than innovation. They came up with a rough, mass-produced product still sold by Colt today.The Marine Corps adopted the 10.5-inch barrel model for the Fleet Antiterrorism Security Teams (FAST), and it was used by DOE, DEA, U.S. Marshals Service, and the U.S. Diplomatic Security Service. The Bahamas, Bangladesh, Malaysia, and Panama also fielded the SMG.
There were several problems with the SMG. A special heavy black buffer was designed to keep the cyclic rate below 1,000 rpm; a standard 5.56mm buffer would run at 1,250 rpm. Because the direct-blowback design created such high bolt speeds, the trigger and hammer pins were upgraded to nickel-plated stainless steel.
 |
Colt 9mm SMG 2 pc mechanical buffer 155.2 grams or 5.47 ounces |
Photo courtesy of http://www.biggerhammer.net/ar15/buffers/
A large deflector was added to deflect the extra gases away from the shooter’s face. This is really important if you shoot left handed. The magazine well is fitted with an adapter to accept modified Israeli UZI magazines.
The Colt magazines have narrow feed lips. They are very hard to load, prone to double feeds, and wear quickly.Inspired by the SMG, several companies have re-invented the AR in 9mm and addressed the magazine issue by adopting the solid and available Glock mags.
With the problem of the magazines solved, now we must move on to excessive bolt speed.The blowback operation of the 9mm AR-15 drives a very heavy bolt (normally 16 ounces) much harder than a standard AR-15 BCG. The energy of the 9mm bolt needs to be dampened to reduce wear, reduce recoil and minimize sight movement.if you take your standard configuration 9mm AR and pull the charging handle all the way back, and look in the ejection port, you will see that the bolt face is a considerable distance behind the bolt catch.
That “running start” to the bolt’s forward travel means that there is a considerable amount of force exerted on the bolt catch, pin, and lower receiver when the bolt catch is activated by an empty magazine.That extra bolt travel doesn’t do anything for function really, it’s just a remnant of adapting a 5.56 firearm to 9mm.
The difference is mostly just the distance the bolt carrier travels to unlock a regular type bolt, versus a blowback 9mm bolt that doesn’t lock. 1/4 to 3/8″ Getting rid of that excess travel does change the shooting feel noticeably. Many builders use a spacer or a stack of quarters to make up this difference. The New Frontier 8 oz buffer is longer solving this problem, no need for a spacer now.
The Standard AR rifle buffer from the original full size ARweighs 5.2oz. The standard carbine buffer is about 3 oz, it has three internal steel weights.
Heavy carbine buffers (traditional design) replace steel weights with tungsten weights. Each time one is replaced, weight increases approximately .8oz.
H Buffer: 3.8oz
H2 Buffer: 4.7oz
H3 Buffer: 5.6oz
Colt SMG 2 piece mechanical Buffer: 5.47 ounces
The NFA buffer shoots softer and runs quieter than any conventional AR buffer. Its weight and length have been optimized for the 9mm application so it runs reliably, softens recoil and stops the bolt just behind the bolt catch using any 9mm ammo type. It dampens bolt impact for a soft landing which completely eliminates spring vibration and noise.For 9mm ARs, I recommends using a SPRINCO Orange AR-10 carbine spring.
