The S in SBCG stands for Secure Staking, Slick Side. SBCG carrier has a
series of serrations or dimples to aid in closing an out of battery bolt
on upper receivers without a forward assist. The carrier still has
forward assist pawl notches, and so is compatible with forward assist
equipped uppers.
The
Secure Staking aspect involves SBCG's use of Ned Christiansen's OCKS
(Optimized Carrier Key Screws), which when staked properly, offer
significant improvement over conventional screws. OCKS have sharp, deep
and effective knurling that extends to the top of the screw head.
These splines form pockets for carrier key metal to flow into when the
key is staked, resulting in gear tooth like engagement. Please go to
this page for additional info and discussion
https://www.m4carbine.net/showthread.php?195130-On-loose-carrier-key-screws
Some argue
that as long as the gas key screws are torqued to spec and staked
properly, OCKS aren't necessary. While that's true, for us,
it is a matter of over building in areas where providing another layer
of fail safe and redundancy is worth the negligible cost. Given the numbers below, the choice of OCKS is an easy one to make.
Install torque spec is 50-58 in-lb
Removal torque spec is 55-100 in-lb
Testing consistently found removal torque of YFS screws averaging around 76 in-lb, with the OCKS consistently at 132 in-lb.
Since
we're so keen on the gas key's staking to ensure its immobility, the
question of one piece carrier had come up. It is our opinion that
something different isn't always something better. Gas keys can crack,
and be dropped and damaged, debris or primer can find its way into the
gas key. Our view is based on reality, not a theory, as all of these
have happened. A conventional carrier with a separate gas key can simply
have its gas key replaced, which is impossible for any one piece
carrier.
Each SBCG has its firing pin protrusion checked, gas
key torqued and staked, and is individually test fired. SBCG will ship
as is, having been slightly lubed and dirtied by the test firing
procedure.
Serrated or dimpled surface is
machined in the concave area (forward of the gas vents of the carrier)
to facilitate silent bolt closing on upper receivers without a forward
assist.
SBCG carriers have a small Cygnus laser
engraved. SBCGs are distinctive looking in their own right (form
follows function, we didn't go out of our way to make them look
different), the subdued logo fits our narrative and practice of modest
to secret logo placement. It's an identifier, not an advertising
device.
* SBCG bolts are manufactured from
properly and correctly heat treated 9310 steel. Each Bolt
is MPI tested and inspected. Each bolt is shot peened and comes with a
Sprinco heavy extractor spring and black O ring. The bolt and cam pin
have been NP3 treated to enhance corrosion resistance and carbon
build up.
* Bolt is stress relieved.
* Sprinco 5-Coil Heavy Duty Extractor Spring
* Black Insert
* MPI tested
* SBCG carriers are 8620 steel and machined to USGI specifications.
The M16/M4 carrier includes a mil-spec gas key. The gas key is heat
treated per TDP specifications and NP3 coated. The gas key is secured to
the carrier via OCKS (Optimized Carrier Key Screws), torqued to spec values, and properly staked.
* Each carrier assembly is treated with a durable Nickel/PTFE plating
which creates a permanently lubricious surface which reduces the need
for lubrication.
Note that we do advocate proper lubrication
between any two moving parts. NP3 coating notwithstanding, it is
advised to apply lubrication on key areas of the carrier, bolt, and
charging handle, and inside the upper receiver.
RE: NP3 coating,
we've been asked to coat SBCGs in nitride or NIB. While our
pre-production SBCGs (all 40 of them) were NiB coated, there will not be
a production SBCG with NIB.
NP3 has a coefficient of friction as low as .07-.1 according to test
standards LFW-1 and ASTM D-2714. Nickel Boron has a coefficient of
friction as low as .08-.2. NP3 has PTFE also known as Teflon®
co-deposited in the nickel matrix. As wear occurs, new PTFE particles
are exposed and the self lubricating properties continue. Nickel boron
has a surface with many high points. Because the high points make all
the contact, there is less surface area for friction to occur. The
problem with this is once the high points wear down the coefficient of
friction increases due to more surface area being contacted. With no
self lubricating particles like Teflon® in the Nickel Boron matrix,
there is no additional lubrication after the contact points are worn.
The bottom line is that if you see wear on Nickel Boron, it has lost its
“Self Lubricating” properties at that spot.
NOTE:
* 2019 and later production SBCGs no longer has NP3 coated extractors.
* SOTAR cam pin is standard from December, 2019 production. For more info on the SOTAR cam pin, please visit this page: https://www.forwardcontrolsdesign.com/SCP-SOTAR-Cam-Pin_p_206.html
*
The time it takes to assemble, QC, testing (including test firing)
SBCGs means we simply don't have time to do that many of them a year,
SBCGs will be a constrained item as long as we uphold the standards we
impose on them, we have no plans to relax our QC standards.
Made in USA.