Hiperfire 24C Trigger – Because Hammer Force Matters

As a precision shooter I’ve never found a trigger that I thought was too light.  Two of my AR-15s have CMC 3.5-pound drop-in triggers, and two of them have Timney 667S 3-pound triggers.

The drawback to light triggers on the AR platform is that there is a limit to how strong the hammer spring can be.  Ammunition with notoriously “hard” primers (e.g., military or Russian loads) will often fail to fire with these match triggers.  I even experience occasional failures to detonate match primers (e.g., FGM205M).  Timney addresses this problem by offering a heavier hammer spring, but that increases the trigger pull of their 667S to 4 pounds.

Hiperfire came out with a brilliant trigger system they call the HIPERTOUCH 24 in which the hammer pivot point is offset and supplemented with two adjustable springs so that the hammer force is lighter when it’s on the sear but heavier when it’s striking (similar to the way compound bows use cams to make the drawn weight lighter than the release weight). Now that it can be found under $200, it is my top pick for AR-15 triggers.

Hiperfire 24C trigger

The result is a 3 pound trigger that hits almost as hard as a standard military trigger.

I tested this against my existing triggers to confirm their claim:

Trigger Pull Weight
(pounds)
Hammer Energy (inch-ounces)
Mil-standard       8.5
18
Timney Heavy       4
18
CMC Match       3.5
11
Timney Light       3
10
Hiperfire 24C       3
16

Testing was done by clamping a rifle vertically and resting a teflon-wrapped rod with a hardened steel head against the firing pin hole.  Pulling the trigger launched the rod vertically, and its peak height indicated the amount of energy that was transferred to it via the firing pin.  Unfortunately, this is hard on the firing pins – especially the Hiperfire’s peak force which I separately measured approaching 20 pounds.  This testing flattened the tips of two firing pins, which had to be retired to a farm upstate where they can run and play with all the other gun parts that can no longer do their jobs.

One thought on “Hiperfire 24C Trigger – Because Hammer Force Matters

  1. federalist Post author

    Terry Bender, HiperFire creator, explains the unique problems of AR triggers and how he addressed them:

    Every trigger option on the market relied on the sear to manage the full weight of the hammer spring, which created a multitude of other issues once the trigger pull was lightened. I set out to design a better trigger to overcome issues of the legacy trigger design itself. The result was a series of patents starting with my 2013 patent that was later released as the HiperTouch 24.

    The problem is that many of those trigger design goals are all opposing forces. A smooth, fast and flat pretravel and crisp, light final break all require low forces at the sear, which equates to the need for lighter hammer and trigger springs, which can lead to light hammer strikes and less reliable ignition. Conversely, very fast trigger resets, minimized lock times and high hammerfall impact require heavy springs, which creates a poor-feeling, heavy trigger. The final dimension is tuning out pretravel, overtravel and ensuring a crisp trigger break, which are all impacted by the above light or heavy springs. Poor tuning can further impact reliability and safety.

    Historically, the compromise has been either a great single-stage trigger that may have a light hammer strike here and there with hard primers, or a two-stage trigger that delivers a first-stage pretravel that some claim slows down followup shots.

    We have a number of patents covering our triggers, however the basis of the design is a camming effect that is caused by an off-center pivot point on the hammer that moves the spring power bias as the hammer rotates. The design allows for a very strong trigger spring, but due to the camming effect, the hammer force is reduced dramatically a few degrees before the sear engagement point. For all the HiperTouch models, this patented design feature allows the trigger pull to be very light while the hammer delivers higher than normal hammer fall energy. The camming effect is achieved via both a proprietary hammer spring and additional dual hammer spring struts.

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