During our research to create a reliable duty grade bolt carrier group, Ned Christiansen of Michigun had been quietly experimenting with superior gas key screws. Given the importance of proper gas key staking, OCKS offers significant advantages over regular cap screws.
1. The Optimized Carrier Key Screw. Sharp, deep, effective knurling all
the way to the top of the head, plus 12 splines. Measured over the
splines, the diameter takes up any clearance space between screw head
diameter and counterbore diameter. The splines essentially are pockets
for carrier key metal to flow into when staking takes place, giving a
2 Three OCKS™; and, on the left is what in my experience is by far the
most commonly used carrier key screw outside the high-end manufacturers.
Maybe, maybe not a bad screw in other applications but note the
indistinct, ersatz knurling. The top edges of the head are devoid of
knurling and have a very rounded, polished-looking surface, making it
nearly impossible for even a good staking job to get a grab on the screw
head. Of the many, many AR15s seen with carrier key screws that have come loose, the vast
majority had this Asia-sourced brand of screw.
3. What they look like staked. Notice how the staked metal has flowed
around and into the splines giving positive, even visually-confirmed,
metal-to-metal engagement. It’s actually even better than it looks since
this carrier key has a pretty generous chamfering of the counterbores. Carrier key metal has formed into the splines from the sides and
even downward from the top.
4. Carrier key sectioned without having first removed the screws, so
that staked material is not wiped or deformed. Flow and engagement with
the splines can clearly be seen. Metal has moved into the splines
from the side and over the top. Also, engagement with the knurling is
We are so impressed with the OCKS, we proudly made them an integral part of our SBCG, where S stands for Secure staking, slick side. Together with the expert staking the craftsmen at Sionics perform on our SBCG, we've created a BCG with significantly increased reliability.
It makes sense then for us to offer Ned's OCKS separately, outside of our SBCG. OCKS is sold as a pair (2 screws). The torque value for OCKS is 50-58 in/lbs.