Care and Maintenance Instructions

27
AAC — BLACK RIFLE MANUAL
ACTION SPRING/BUFFER
The 16 inch upper with a carbine length gas system
should use a “C” rated buffer. All other uppers should
use an H2 buffer (160 grams). H3 buffer may be a
good choice if you don’t intend to shoot subsonic
without a sound suppressor or typically shoot
supersonic ammo. Do not use a solid 9mm buffer as
it may cause bolt bounce.
EXTRACTOR SPRINGS
We have 5.56mm test data for the Bushmaster ‘4 coil’
extractor spring with an o-ring. Four uppers completed
a 12,000 round test with no extractor spring related
failures. Two uppers completed an 18,000 round test
with no extractor spring related failures.
We do not recommend using
extra-power extractor springs
because they are under higher
stress and will likely break sooner. The included green
o-ring adds the desired extra extractor force without
requiring a spring which would have more force
and hence more stress. Extra-power springs, when
combined with an o-ring, may make the extractor
harder to snap over the case rim and may lead to
function problems. If you do use such a spring, please
don’t use an o-ring and change the spring every 1500
rounds for mission-critical use. The green color of the
o-ring signifies that it meets AAC specifications for
endurance and elasticity at low temperatures.
NOTE: Again per our spring discussion, Chrome Silicon
springs do not resist taking a set better than ASTM
A228 certified music wire when used at temperatures
below 250 degrees F.
PARTS REPLACEMENT
The Gas block is press-fit and pinned and may not be
removable or replaceable without a press. Additionally,
set screws are secured with both torque and Rocksett.
If you remove the gas block, reset the set- screws to
30-35 inch/lbs of torque and one drop of Rocksett.
The following recommended replacement schedule for
parts depends on the intensity of use and the intended
use. After any parts replacement, give the firearm a
safety/function check before use.
MAGAZINES
AAC 300 BLACKOUT ammo can feed from standard
USGI or Magpul P-Mags. A magazine with the standard
MIL-STD 17-7 stainless spring may be stored fully
loaded with 30 rounds indefinitely. Note that Chrome
Silicon springs will not resist taking a set better than
MIL-STD 17-7 magazine springs regardless of how they
have been marketed.
SOUND SUPPRESSORS
The recommended sound suppressor is the AAC
762-SDN-6. This has been tested to provide a good
balance between sound level, weight, accuracy, and
reliable function. Suppressed SPL with AAC subsonic
ammunition is approximately 126 dB both using MIL-
STD measurements and at the shooter’s ear.
AMMUNITION
There are two special considerations for the AAC
upper - gas port pressure, and reliable feeding
from a magazine. 300 AAC BLACKOUT (300 BLK)
ammo from Advanced Armament Corp. is designed
for reliable function in self-loading firearms. Visit
www.300AACBLACKOUT.com for ammunition
information.
USER MODIFICATIONS
The gas-port diameter was selected after thousands
of rounds of function testing and high-speed video
analysis. We do not recommend you enlarge your gas-
port to aid subsonic function because then supersonic
ammunition will hyper-cycle the upper which will
reduce the reliability and part life durability of the
system. AAC has developed subsonic and supersonic
ammo that both function reliably (with and without an
AAC 762-SDN-6 sound suppressor) without the need
for an adjustable gas block.
BARREL LIFE
The barrel of the AAC BLACKOUT upper is made from
4150 CMV and specially processed to have
up to 60% more life than a chrome-lined barrel and
without the potential loss in accuracy from uneven
coating. This processing also results in extreme
corrosion resistance.
9” PDW UPPER
RECREATIONAL USE
When fails
When fails
10,000 rounds
When fails
15,000 rounds
15,000 rounds
50,000 rounds
15,000 rounds
PART
Gas Tube
Extractor
Gas rings
Bolt
Extractor spring/insert/o-ring
Ejector spring
Barrel
Action spring
HARD USE / COMPETITION
10,000 rounds
10,000 rounds
5,000 rounds
10,000 rounds
5,000 rounds
10,000 rounds
35,000 rounds
10,000 rounds
MISSION-CRITICAL USE
5,000 rounds
5,000 rounds
5,000 rounds
5,000 rounds
5,000 rounds
5,000 rounds
20,000 rounds
5,000 rounds
REPLACEMENT PART NUMBERS
Firing pin retaining pin, Bushmaster part 8448504
M16 Chromed Steel Firing Pin, Bushmaster part 8448503
Extractor pin, Bushmaster part 8448513
Extractor, Bushmaster part 8448512
Ejector assembly, Bushmaster part A EJECT ASS
Cam pin, Bushmaster part 8448502
Bolt Gas Rings (set of 3), Bushmaster part 8448511K
Charging Handle, Bushmaster part 8448617
ALWAYS CHECK HEAD SPACE AFTER CHANGING A BOLT, BARREL, OR BARREL EXTENSION.
LIMITED ONE YEAR WARRANTY
ADVANCED ARMAMENT CORP. (AAC) Firearms and
accessories are warranted to be free from defects in
materials and workmanship. Any such defect of which
AAC is given written notice, as provided below, within
one year and ten days from the date of first purchase by
a customer will be remedied by AAC. This warranty is
granted by ADVANCED ARMAMENT CORP. 2408 Tech
Center Parkway, Suite 150, Lawrenceville, GA 30043,
USA.
To initiate a Warranty claim, call AAC
(1-770-925-9988) to get a “Return Merchandise
Authorization” (RMA) number. Warranty claims should
state (in writing) the model and serial number of the
product concerned, a description of the difficulty
experienced, and the date of purchase. The product
concerned should be shipped (transportation charges
prepaid), to the Warranty Service Department,
ADVANCED ARMAMENT CORP. 2408 Tech Center
Parkway, Suite 150, Lawrenceville, GA 30043, USA.
Shipment should be insured by the owner, as AAC will
accept no responsibility for loss or damage in transit.
Under no circumstances shall ADVANCED ARMAMENT
CORP. be responsible for incidental or consequential
damages with respect to economic loss or injury to
property, whether as a result of express or implied
warranty, negligence or otherwise. Some states do
not allow the exclusion of limitation of incidental or
consequential damages, so the above limitation may
not apply to you. ADVANCED ARMAMENT CORP.
will not be responsible for the results of careless
handling, unauthorized adjustments, defective, low
quality, reloaded, or improper ammunition, corrosion,
neglect, ordinary wear and tear, or unreasonable use.
Furthermore, the liability of ADVANCED ARMAMENT
CORP. under this warranty shall be limited solely to the
obligation to repair or replace the firearm or accessory,
and to pay transportation and insurance charges for
return of the firearm or accessory to owner.
NOTE: Handguns and long guns are classified as
FIREARMS or DANGEROUS WEAPONS. Guns are
surrendered by ADVANCED ARMAMENT CORP. with the
express understanding that it assumes no responsibility
for resale handling under local laws and regulations.