How to Build a Bufferless AR (Instructions)

want to ditch that buffer tube once and for all? Got an AR-9 to do it? We're covering how to put together -- or swap your current upper for -- a bufferless 9mm upper! These instructions apply for our 5" right-side charging bufferless upper assembly.

NOTE: At this time, only the 9mm AR platform is compatible with the bufferless upper assembly shown below.

How The Bufferless Upper Works

The bufferless upper works by eliminating the AR-15's standard buffer tube, replacing it with what is effectively an ultra-compact tube (pictured middle, above), contained inside a large end cap that doubles as the receiver's latch plate (pictured left). 

The modified bolt inside the upper receiver is cycled by an internal operating rod and recoil spring. One end of the rod and spring rest inside the end cap. The opposite end of the rod and spring feed directly into the bolt carrier group, pictured above.

(Existing Uppers Cannot Be Converted)

Note that standard stripped upper receivers (pictured top left) cannot be modified to operate as a bufferless assembly, as the bufferless bolt carrier group won't fit inside a standard upper receiver.

This is because the proprietary BCG is physically wider than the standard BCG. The tunnel inside the bufferless upper, wherein the bolt carrier group resides, is machined to be wider to accommodate its shape (pictured top right).

How to Install The Bufferless Upper

In addition to the barreled upper assembly and preinstalled bolt carrier group, ensure your bufferless upper assembly includes each of the following, pictured above from left to right:

• Rod & Spring
• Allen Key
• Retaining Bolt
• End Cap w/ Rail
• Threaded Tube Insert

#1: Remove Buffer Assembly From Lower

(If beginning a new build with a fresh lower receiver, skip to step 3)

First, remove the existing barreled upper assembly from the AR's lower. Pull out both the front pivot pin and rear takedown pin, then firmly grasp the upper receiver and pull it up and out from the lower receiver.

Next, secure the lower receiver in a tabletop vise. Ideally, the receiver should be secured in the vise using a receiver vise block. Otherwise, wrap the receiver in a soft cloth to prevent the vise from damaging the receiver's finish. 

Take care not to clamp the receiver in such a way that its fire control components -- like the bolt catch lever or safety lever -- cannot be damaged by the vise.

Now loosen the castle nut holding the buffer tube to the receiver with an Armorer's Wrench. 

Once the castle nut is loose, the buffer tube can be threaded and removed from the receiver. Before attempting to remove the tube, the buffer retainer inside the tube housing's threads must be depressed. 

Press down on the tip of the retainer using the provided Allen Key.

While depressing the retainer, rotate the buffer tube counter clockwise until it is separated from the lower receiver. 

Note that the buffer retainer is under spring tension; take care not to allow it to fly out of the receiver once it is free from the buffer tube.

Once the buffer tube, castle nut, and latch plate are separated from the lower receiver, take care to ensure the rear takedown pin's detent and spring remain in the hole in the back of the lower receiver. The new end cap will secure these components, like the latch plate once did.

#2: Install Threaded Tube Insert

Replace the original buffer tube by threading the end cap's threaded tube insert into the lower receiver. Its orientation is unimportant. Use a large adjustable wrench on the flats at the end of the insert to tighten it.

#3: Install End Cap

Next, slide the end cap over the threaded tube insert. Note the bottom front face of the end cap acts as a latch plate. Ensure this face captures and secures the rear takedown pin spring, without crushing it.

While pressing the end cap flush against the rear of the lower receiver, insert the provided bolt through the hole in the rear-facing Picatinny rail. Tighten the bolt with the provided Allen key to secure the end cap to the lower receiver.

#4: Install Operating Rod & Recoil Spring

Slide the provided recoil spring over the operating rod. Then insert the capped end of the operating into the hole at the top front of the end cap. 

Note the discoloration of the end of the operating rod is normal; it is heat-treated and hardened to withstand wear during cycling.

#5: Install Upper Receiver

It's easiest to install the upper receiver by rotating it 90 degrees, allowing for easy viewing and alignment of the operating rod, recoil spring, and bolt carrier group.

Ensure the end of the recoil spring and operating rod seat inside the bolt carrier group. Once the spring is aligned and seated, push the upper receiver back toward the end cap, compressing the spring.

Rotate the upper receiver vertical, align its lugs with the pivot pin and rear takedown pin, and press both pins in to secure the upper.

Your Bufferless Upper Install is Complete

Your bufferless AR's ready to go! 

Functionality: Once assembled, your bufferless AR9 will function like any other AR-type rifle or pistol. Just insert a magazine and charge the weapon by pulling back on the charging handle. The fire control components, including the hammer, safety, and trigger, and the bolt catch assembly all retain their original function.

WARNING: Installing a folding buttstock (or any other stock) on the end cap will result in the creation of a short-barreled rifle (SBR). Ensure your AR9 is registered accordingly before installing any stock (here's how to do it).

Note the hole machined the rear slanted portion of the end cap is a QD mount for a sling. Grab a sling here!

Want to convert your AR9 into a bufferless pistol or SBR? Buy this upper!