Making the SIG P320 Better with the Apex Tactical Specialties Trigger Kit – Review

By Mark Miller

The Apex Tactical Specialties SIG 320 Trigger Kit for factory upgraded models of the Sig Sauer P320 is a direct replacement to the factory trigger bar and curved trigger. Machined from billet steel and made in the free state of Arizona, the kit is easily installed without the need for tools or fixtures.

My friends are tired of hearing me talk about the Sig P320. It is not just another handgun. It is changing the gun world in ways we are just beginning to understand and will fundamentally change the way we buy and modify guns forever.  The Apex trigger is a critical part of this evolution. The Army bought the Sig P320 as the M-17 Modular Handgun System. What provides the “Modular” feature of the P320 is the Fire Control Group (FCG). According to ATF, (the only opinion that matters), the serial numbered FCG is the gun. All the other pieces are just parts, transferable without regulation.

Factory triggers don’t have a great reputation from any manufacturer.  There are many reasons for this. Good triggers are expensive, heavy triggers carry less liability, the requirements of mass production may not optimize trigger function and existing patents restrict trigger design options.

Why are Apex triggers worth the cost and trouble? Apex pulls out all the stops. They look at what shooters want. They are shooters. They take one gun at a time and come up with the optimal geometry and feel. They test and test. Then they produce the trigger and charge a fair price.

Apex combines precise manufacturing and high-quality materials. They own some of the best patents. The patent-pending Apex Forward Set Trigger Bar reduces trigger travel and reset. The Apex Flat Advanced Trigger reduces the trigger pull weight and increases trigger reach to the natural resting position of the shooter’s finger. This allows the shooter to position their finger lower on the trigger face to take advantage of the increased leverage.

I find that this design puts my finger at an optimal position and provides an index to keep it there. There is a lip at the bottom where my finger rests, the same place each time. The flat faced trigger helps me feel the trigger geometry to pull straight back. This trigger has a much different feel than stock and provides an intuitive sense of what is happening with your gun.

The SIG P320 has seen its share of controversy. It has been derided by many who have never touched one. Since its inception, there have been constant improvements made to the SIG 320. There is a factory upgrade available at no cost. I have one of the early 320’s. I went online and registered for the upgrade. Two days later I got a shipping label and within two weeks, I had my upgraded gun back, better than ever.

This Apex trigger is ONLY for use in the “factory upgraded” models of the P320 which have the full complement safety enhancements (including the X-Series). If you don’t have the upgrade, send your gun to SIG and get free stuff. However, due to different internal dimensions of the mold, use in the Sub-Compact Grip Module is NOT recommended.

Not for use in Thumb Safety models of the P320.

Does NOT function in the Sig Sauer P250.

Some good news for shooters who play USPSA: As of May 15th, 2018, this trigger kit is legal for use in USPSA’s Production Division (please see Appendix D4, section 21.6, of the USPSA Production Division rules).

Expected Results

– Direct drop-in replacement of factory trigger bar and curved trigger

– Reduces trigger travel approx. 30%

– Reduces reset approx. 20%

– Reduces trigger pull weight by approx. 30%

– In X-Series models, does not reduce pull weight but does reduce overall travel 30%

– Maintains factory drop safety values

What you get In the package

1 ea. Flat Advanced Trigger

1 ea. Forward Set Trigger Bar

1 ea. Over-Travel Stop

1 ea. Over-Travel Stop Spring

Installation Resources

I was a little intimidated by the SIG 320’s Fire Control Group. I have some experience with the Classic model SIGs and they are less than friendly. The 320 is very simple and in Apex’s fantastic video, Scott Folk walks you through how to properly install your Apex Forward Set Trigger Bar Kit in the Sig Sauer P320 pistols. Three tools and ten minutes later I was done. It worked right the first time.

Apex recommends that a gunsmith perform this work. Whenever you change trigger parts, you run the risk of causing safety problems. If you are not comfortable performing the work shown in the video, have a SIG armorer of gunsmith install your kit. It is not difficult, but it is essential that it be done correctly.

I liked the original 320 trigger. It had some slack in it but it was smooth and fairly light. The Apex trigger turned the 320 into a different gun. The flat trigger and the “tail” at the bottom places your finger in the optimum position by feel. Intuitive and easy, shooting is smooth and fast. The trigger activates when you need it without moving the sights. The trigger pull is smooth and the re-set is short. Shooting plate racks and Texas stars is the best way to feel the difference.

Apex turned my mundane full sized .40 cal Sig 320 and my 9mm Carry into high-performance shooters ready for everyday carry or competition. I can’t wait to get out to the range again and push myself with this trigger. There is no excuse; the trigger is excellent; your shooting should be exceptional.

The open design architecture of the SIG 320 along with increasingly available home manufacturing capability will let hobbyists take control of their guns in ways not possible before. Not only changing size and caliber on a whim but making functional and truly custom guns tailored to the individual shooter. The Sig 320 is a good gun. As it evolves, it will become a customized perfect gun for each shooter. The APEX trigger makes the 320 the shooter much more responsive to the gun.

About Apex:

Apex Tactical Specialties, Inc. was created to serve Law Enforcement personnel, competition shooters, and individuals who recognize the need for defensive tools to be more than “just adequate” for the job. We are a quality-driven and progressive organization – our product line, services, and expertise are continually evolving. Our mission is simple: superior parts, exceptional performance and craftsmanship, and above all, unparalleled customer service.

ATS, Inc. will not fit, install, or endorse any products that have not been thoroughly tested and evaluated by our staff. Personal experience, extensive field-testing, and follow up failure analysis are the essential methods by which we evaluate components that we recommend and use. It is not sufficient to just know that a part will work: we need to know why it works, and the limits of its operational envelope.

Learn more about Apex by clicking here.

***Shop GunsAmerica for your next Apex Trigger***


About the author: Mark Miller is a former Customs Agent and a Green Beret who served in Afghanistan and a number of other live fire locations. A student of firearms and shooting, he is an FFL and a SOT. The guiding philosophy of his life is that terrain and situation dictate tactics and the enemy always gets a vote on any plan.

{ 7 comments… add one }
  • Bill October 30, 2020, 7:09 am


  • David Rockwell July 23, 2018, 9:23 am

    Installed the Apex forward set flat trigger on my Sig 320RX. Love the forward reset, fits my finger length much better. The flat trigger works well for me. Makes for very consistent finger placement.
    Problem is, trigger pull went from 6 1/2 lbs with some creep, to 8lbs with some creep. Apex customer service was very responsive and helpful. Went through install again, stoned down pins, and polished every imaginable engagement surface. No significant change. Still 8lbs.
    Finally just gave up. Maybe it will settle in some with useage.

  • Paul July 2, 2018, 2:31 pm

    I could have very easily written this article. I have two 320s a compact and a sub. I installed the first model APEX triggers a long time ago because I really prefer the flat faced trigger. It’s a big improvement over the original curved (hooked?) trigger. The early APEX didn’t come with the transfer bar. I loved the new feel of both guns. Then came the big “drop” issue. I sent both guns in for the recall. The first one, the compact took about eight weeks to get back. The little sub came back in nine days. For some unexplained reason the sub had also been returned with a new frame.

    After I got them back, again with the curved trigger, I ordered two of the new APEX flat trigger/transfer bar kits for guns that had been through the recall. The install is easy with just a few common tools. I hand polished each piece as I reinstalled the action. Both guns now have amazingly good triggers and I am very pleased. Note .. this the first I’ve heard about not using the APEX in a sub-compact. I never read anything from APEX on this. My little sub runs perfectly with the mods and is used in my EDC rotation. I don’t see any problems with it and it is by far the most accurate small 9mm I’ve ever seen. In over 3500 shared rounds I have yet to experience a single failure or jam of any kind with the sub and ONE single FE with the compact, using some steel case ammo. I love these guns and plan on adding an X5 to my 320 collection and probably an APEX rebuild on it too.

  • Samuel Summey July 2, 2018, 10:21 am

    Flat faced triggers are the most un-natural feeling trigger I have ever dealt with. Recently another gun shop brought a Sig P290R (I think that was the model) that they had installed another manufacturer’s product in. It wouldn’t reset. The gun was “brand hammer new”‘ with no wear on the internals. After dis-assembling and reassembling per the manufacturer’s You Tube instructions and lubing I began dryfiring the handgun, after around 300 cycles the trigger got more reliable, at 500 cycles it was working perfectly. The feel of the straight trigger with a ridge on the tip is the most un-natural feeling trigger I have ever experienced in my 56 years of shooting all kinds of guns.

    • Jeffrey Hunt July 4, 2018, 11:00 pm

      Be careful dry firing the P290. Sig warns you may damage the firing pin if not using snap caps.

  • Ryan kane July 2, 2018, 8:32 am

    Why cant the apex triggers look better?

    • Paul July 2, 2018, 2:42 pm

      I think the APEX trigger look great, much better than the stock Sig triggers. And they really look really good after you’ve gone down range and looked at your targets.

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