Geissele MCX Triggers Now Available

Geissele has made a trigger for the Sig Sauer MCX. In their Facebook post they claim that an MPX trigger is coming soon. That will be most interesting to see. For those who do not follow MPX accessory development, after market triggers are a ticking time bomb in the MPX.


Here is an email someone got from Geissele earlier this year.

Good Morning.

Thank you for contacting us. In regards to our stance on our triggers in the MPX and MCX, as the industry grows, there are more and more AR variants out there that accept AR15 fire control groups. Each one is different and though we would like to, we have not tested our AR15 triggers with any of them. What we know about our triggers in the MPX we have learned from feedback from our customers. From the beginning, our customer service representatives have explicitly told people that we have not had any experience with our trigger in the MPX/MCX. We have stated that forum users have claimed to have success but we cannot confirm their success. We have never strayed from this and have never confirmed our trigger work in those platforms, and have always maintained that our triggers were designed to function with a mil-spec M4 carbine. With that said, the MPX has a very fast action, which is why the MPX ships with the trigger bridge, to protect the fire control group from the action. The MPX was designed to be used with the trigger bridge, our triggers were designed to be used with AR15 rifles using mil-spec components. While the MPX combination will work for a while, it will eventually fail. We want to be clear with our customers on this, and also have them know that we are working on an MPX specific trigger. We do not recommend using our AR15 triggers in these variants as it will void our warranty.

Going forward, rebuild kits for our AR15 triggers installed in the MPX will be available for a fee. The SSA-MPX trigger group is currently in development and will incorporate a trigger bridge to alleviate the current issues. It is slated for release in 2017. Unfortunately the SSA-MPX trigger is still in development and the price has yet to be determined as well as a definitive release date. Right now, we are not offering a trade in program.

As for the recent MCX recall, we have just recently heard of this recall and we are still working out all of the details. Right now, we cannot confirm this information. Once we get more information about this issue, we will let everyone know. I hope this helps.


From what I have heard, after market hammers have a tendency to break. AS the email above noted, the SIG MPX trigger has a hammer bridge. As seen in the rendering below.


Some companies have claimed that their triggers work in the MPX. Franklin Armory is one of those companies and I have personally been running a BFSIII Trigger in my Gen 1 MPX. I know quite a few USPSA competitors are running Hiperfire triggers in their MPXs as well but do not know the longevity of them in the MPX.

We shall see what Geissele comes up with. Hopefully we will see them again at the Big 3 East Media Event this October.

Nicholas C

Co-Founder of KRISSTALK forums, an owner’s support group and all things KRISS Vector related. Nick found his passion through competitive shooting while living in NY. He participates in USPSA and 3Gun. He loves all things that shoots and flashlights. Really really bright flashlights.

Any questions please email him at


  • Dracon1201

    Kind of odd for the MCX. My SD3G trigger hasn’t failed in mine.

    • Nicholas C

      Not sure about compatibility in the MCX. Haven’t heard any issues regarding the MCX. It is the MPX that is the problem.

      • Dracon1201

        So my question is, why bother for the MCX? Marketing?

      • Joe

        When they had their BCG recall, they replaced all aftermarket triggers with Geissele’s (on their dime) because they said standard AR-15 triggers were not compatible with the new BCG.

  • FearlessFarris

    I’ve been running a Geissele trigger in my MPX for nearly two years now, without issue. I’ve never been let down by a Geissele trigger, and have them in every firearm I own that will take one. I’m disappointed to hear that Geissele is no longer honoring it’s warranty on triggers in MPXs, since I believe their previous position was to honor it.

  • datimes

    The trigger and charging handle are my two biggest complaints with my MPX. I was thinking of selling it but there is a cure for both now.

    • Adam D.

      What brand/type of charging handle?

      • datimes

        It comes standard on the gun. Too small and sloppy.

        • Adam D.

          Yes, I know owners don’t like the factory charging handle,
          but you wrote “there is a cure for both now”, that’s why I asked what brand of “cure” did you mean by that.

          Since then I’ve found the product though, I guess you meant the Next Level MPX charging handle, right?

          I’ve read that AXTS/Radian also plans to come out with an MPX specific Raptor in the near future.

          Are the Gen 2 factory charging handles still bad by the way?

          I know they’ve changed to an ambi latch with the Gen 2, but haven’t seen it in person.

          • datimes

            Next Level has a new handle that solves the problem and new triggers (Geissele) soon to be available.

  • Adm

    Aftermarket triggers aren’t working with the mcx post recall bcg mainly due to the height of hammer. They are just slightly too short to properly disengage the cam of the new firing pin block. A simple solution is to remove the trigger and replace the rifle.

  • Cal.Bar

    Funny, I’ve been running a Geissele in my MCX for months now without any problem. (of course I haven’t sent it back to be screwed with either.) If it’s not broken… don’t fix it.