Manual

5.56/.223, wide end in ﬁ rst. Pistol cal, slim end in ﬁ rst.

• Unload and clear your riﬂ e following the

manufacturer’s recommendations and remove the

upper receiver from the lower receiver. Move the

hammer to the cocked position and put the safety

selector on “SAFE”.

• CAUTION: The buffer and spring are under tension.

Be especially careful to not point the lower receiver

in a manner that would allow the buffer and/or spring

to launch from the lower receiver and cause damage

or injury.

• Press down the buffer detent (Step 1) and remove

the buffer weight and spring. You will need to press

the hammer down to allow the buffer and spring to

pass over (Step 2).

• Check the receiver extension tube for obstructions.

Remove anything in the receiver extension tube; it will

need to be empty to install the AC4.

Installation

(Additional notes on back side.)

• Insert the AC4 Pneumatic Recoil Buffer into the

receiver extension tube. Be sure to turn the AC4 in

the correct direction based on whether you are using

5.56/.223 or pistol cal. See Step 3 photos.

• Push the AC4 Pneumatic Recoil buffer into the

receiver extension tube and past the buffer detent.

See Step 4.

• When properly installed, the AC4 Pneumatic Recoil

Buffer will be ﬂ ush with the receiver extension tube

and be held in place by the buffer detent.

Pneumatic Recoil Buffer - Non-Adjustable

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Pneumatic Recoil Buffer - Non-Adjustable Installation (Additional notes on back side.) • Unload and clear your riﬂe following the manufacturer’s recommendations and remove the upper receiver from the lower receiver. Move the hammer to the cocked position and put the safety selector on “SAFE”. • CAUTION: The buffer and spring are under tension.
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This model of AC4 Pneumatic Recoil Buffer is not adjustable. It has been designed for AR-15 riﬂes and carbines that have full length receiver extension tubes (i.e. A2 buttstocks, non-stubby ACE stocks). It is very important to note that the AC4 does not work in collapsible stocks because the receiver extension tube is too short. The label on the non-adjustable AC4 will specify that the buffer is for either “5.56 / .223 AR Riﬂes” or “Pistol Caliber AR Riﬂes”.