ASF (Ambidextrous Selector, Forward Controls) was conceived in late 2018 as a duty/combat grade safety, with ergonomics, reliability and robustness as its top priorities.
The design goals laid out for ASF are as follows:
1. Levers attach to the center via roll pins. We do not want any wobbly or slack on the levers.
2. No MIM or cast. To achieve the rotational smoothness and positive detent engagement, as well as tight fitting levers, we'd be holding very tight tolerances.
3. All steel construction. We're sticking to TDP material on this. While it's our belief aluminum levers would be acceptable, we see no reason to deviate from TDP specs on mateiral and heat treat specs.
4. Levers designed to aid users, the shapes of which are derived from the functions they perform. Fashion isn't a function.
ASF is available in the following configurations: 90 degree semi, 50 degree semi, conventional M16 (0-90-180), and short throw M16 (0-50-180) where SAFE to SEMI is a 50 degrees rotation, but AUTO/BURST is 180 degrees from SAFE. There won't be pictures or discussion on the centers in this article, as much time as we spent in getting the the rotational smoothness and detent engagement just right, pictures would nearly constitute revelation of trade secrets.
It was fairly straight forward to derive at lever shapes that do what we ask of them. The serrations on the lever run along the length, not perpendicular or diagonal, as when the user rotates the safety, his finger is sliding on the lever where the presence of friction and traction is decidedly unhelpful. ASF short levers are wider than the long lever. Its short length gives up surface area, we put some lost surface area back by increasing its width.
ASF long q lever (left) and short q lever (right) shown, the additional width of the short lever can be seen. Also note the relief cut on the long left q lever's for the selector stop.
Also worth noting is the profile of the levers. ASF's levers have a 90 degree surface to the receiver, with a portion of it sloped. The serrations along the length of the lever do not impede the finger from sliding on it lengthwise, but mitigate lateral movement. The user's thumb is naturally at an angle when it's resting on the lever, the partially perpendicular, partially sloped lever profile doesn't fight with the user's finger for dominance.
ASF levers have two major groups: standard, non-offset levers, and offset levers (q levers). Within each group, there are long and short versions.
Standard, non-offset levers shown below:
Offset levers (q levers) shown below.
Standard, non-offset levers can be installed on either side of the receiver, while offset levers (q levers) are side dependent. The offset levers are designed to place the lever closer to the user's thumb when the selector is set on FIRE/SEMI, to enable him to access it without shifting his grip.
A q lever should always be above the lever's center interface hole when installed on the receiver, as shown below.
The q lever works as designed. With an averaged adult male's hand, the user no longer needs to shift his grip to rotate the lever from FIRE/SEMI to SAFE. The offset isn't exaggerated, it doesn't need to be to do what it's designed to do.
All ASF levers have an angled flat. When the selector is switched to SAFE, this flat is designed to reduce drag and snagging when the user pulls or drags the rifle in low crawl. This area also doesn't contribute to the lever's strength, so it has material removed.
Instead of a line or triangular pointer, we use a dimple milled at each end of the ASF centers as position indicators. Whenever possible, we prefer simplicity and minimalism.
The use of 420 stainless steel roll pin (breaking strength: 800lbs) was one of the requirements. We don't use screws that can loosen and back out, or other means of fixing the lever on the center that produces loose and wobbly fitting levers, as they have no way of tightening the lever to the center. ASF's lever attachment system isn't new or a novelty, it's been used on other designs before, we see no reason to develop something new but not better. The lever to interface design is quite robust, the high strength 420 SS roll pin doesn't handle any load or torque, both are handled by the ASF center and lever, the pin only serves to keep the lever from detachment.
Below is a picture of ASF short, non-offset lever prototype that shows the roll pin. From this picture, the 0.001 tolerance we hold on ASF center's and lever's attachment interface can be seen. The very slight, almost imperceptible movement is wholly eliminated when the 420 stainless steel roll pin is driven in.
4 420 stainless steel roll pins are provided. 2 are are required, and 2 are spare.
ASF centers are not reversible, this is by design. We have thought this through and have our reasons against it. First is users either want a 90 degree conventional or short
throw, we don't know if a lot of users on the fence about it. Two is
cost, to us and the user. Only one side can be used at any given time, but
the other side is always there, and it needs to be machined. The user can't
use it, but he would have paid for the machining of the detent holes and groove.
We decided to keep it simple, and what serves the user's interest, we believe a reversible represents an unnecessary cost. Having to stock 2 different semi auto centers isn't what's best for us, but FCD
doesn't exist for our convenience, 2 separate centers is what we believe
to be better for the users.
ASF is a collaboration with Sons of Liberty Gunworks. Made in the USA.