There’s been some extra buzz in the firearm industry lately about modular fire control groups. You might know that it has something to do with triggers and laws about firearm purchases, but why are people getting so excited?
Call it a fire control group, fire control unit, fire control insert, or central operating group — those are all manufacturer terms for the same thing: a serialized trigger mechanism that you can take out of one pistol and install in another right at home with nothing but your own two hands.
Fire Control Basics
The specific components and design of a fire control group vary from platform to platform, but you can think of them as a collection of parts like the trigger, sear, a few springs, and safety mechanisms.
In something like an AR-15, these components often interface with the lower receiver that holds everything together. Sometimes, manufacturers package them as one unit that drops into the receiver, frame, or grip module. This makes it easier to replace at home if you want to upgrade to a higher-performance FCG or move it to another firearm — in this case, from one handgun to another.
Just look at how easy this is.
The most significant feature of the fire control groups we’re talking about isn’t the trigger, sear, or any other functional piece — it’s the serial number. By serializing the FCG, the manufacturer turns it into a firearm in legal terms. That means everything else — the frame, slide, barrel, you name it — is an accessory in the eyes of the authorities.
This matters because firearm transfers require a federal firearms license but accessory sales do not. You can change every single thing about your pistol except the fire control group right at home with parts that you bought over the counter or had shipped to your door.
Which Pistols Have a Modular Fire Control Group?
Sig Sauer made the idea of a modular pistol fire control group mainstream with the fire control units of the P320 and P365. Even if most owners never remove their FCU, the concept works. You don’t even need tools because the takedown lever holds the FCU in place and you can remove that with your hands.
The Springfield Armory Echelon uses the same principle but it’s branded as a central operating group (COG) instead of a fire control unit. The COG is compatible with full-size and compact Echelons, and Springfield offers multiple grip sizes for each.
Ruger just announced the RXM. You’ll recognize it as a Glock-pattern pistol but, unlike the Glock 19, it uses what Ruger calls a modular fire control insert. Since there’s no advantage to using this modular approach in a standalone model, I suspect that Ruger has more RXM configurations on the way.
How a Modular Fire Control Group Can Save You Money
Modularity is a huge selling point for all these pistols. You can buy an entry-level pistol, and then upgrade components at your own pace. You can also create specialized tools like a carry pistol, competition pistol, and duty pistol that all use the same platform (P320, P365, Echelon, or RXM) and only pay for one fire control group and one FFL transfer. As long as you don’t need multiple pistols at the same time, they can all share a fire control group.
Another advantage of this concept is the ability to build a custom firearm yourself. Instead of investing in specialty tools and advanced training, you can buy a performance fire control group from the original manufacturer and add a barrel, slide, frame, and accessories from aftermarket suppliers to get exactly what you want.
It’s also worth pointing out that, because the fire control group exists either inside the pistol’s frame or trigger guard, it has no bearing on holster compatibility. For example, you can upgrade your Sig with a competition trigger, and it’ll still fit in all your existing holsters.
So why do we love modular fire control groups? Because they’re fun! They let us save money and exercise our creativity. That’s a design concept I can get behind.
