I’ve often been asked by readers to pick between two guns for them or directly asked, “If you could only have only one gun….” I rarely provide an answer to either question as I firmly believe handgun selection depends heavily on intended use and personal preference, but the expansive aftermarket for the modular SIG SAUER P365 may have provided the answer for us.
I bet the mental image “P365” brings differs for each person. That’s in part due to the scores of models and configurations available, and yet they are all technically the same “firearm.”
During a visit to SIG in 2024 we were told there were over 200 P365 variants. Google’s all-knowing AI claims there are 22 main model SKUs. The entertaining fact is that no one seems to have an exact number of the total options out there, but it doesn’t really matter because the platform’s modularity is what allows the P365 to flex between different roles.
If you want a pocketable 10+1 round carry gun, the P365 can absolutely do that. If you want a 4.3-inch barrel, 21+1-round range or duty gun, the P365 can do that, too. The best part is, especially for those who live restrictive states, it can all be done with the same “firearm.”
SIG wasn’t the first manufacturer to use a chassis-style design for handgun manufacturing, but they were the first to make it part of the ownership culture and to really support the aftermarket. The P365’s fire control unit is legally the firearm and the only part that requires FFL paperwork and handling. You can even buy just an FCU and then select your grip size and slide length later.
Everything else besides the FCU can be shipped directly to your door. Instead of closely guarding the dimensions in a grip needed for the P365 FCU to fit and function, SIG was smart enough to share that information with aftermarket manufacturers, clearing the way for companies like Icarus Precision, Sharps Bros., and dozens more to not only create grips, barrels and slides that SIG doesn’t, but to further expand the user base of P365 owners.
As a result, companies like Icarus Precision were able to create grip module designs previously unavailable such as those with Picatinny rails and full-length dust covers. Sharps Bros. has created multiple models that, when combined with replaceable grip panels, widens the skinny P365 profile out to the 1.2-inch width to approximate the hand feel of a traditional compact and distribute recoil over a broader part of the hand.
With one FCU you can swap grips and slide assemblies and turn your tiny pocket pistol into a full-size gun in less than a minute. It’s not inexpensive, but you maintain the same trigger feel and as far as the government, your significant other, or anyone else is concerned, you still just have one firearm.
Companies like Maskas Precision allow you to alter the ballistic performance and recoil impulse of your P365 with complete slides of both factory and alternate slide lengths.
Just before SIG released the P365 FUSE, Maskas launched a XXL slide which extends the barrel to 4.1 inches and reaches that critical 4-inch mark for which most American defensive ammunition is loaded to perform best. Paired with the Macro-sized Sharps Bros. grip module the little P365 is now about the equivalent of a slim, classic, very capable compact 9mm with extra capacity. That slide can also be paired with a P365XL for those wanting to keep the smaller grip, but hit targets a little harder.
The aftermarket has even begun to respond to other preferences shooters might have. For example, the Tyrant CNC IntelliFire trigger adds the safety dingus that some prefer.
I wasn’t able to confirm other claims as to the IntelliFire’s performance enhancement abilities, but I’ve noticed that across the five P365 FCUs I own, the trigger feel isn’t universal. I attribute that to rolling changes in production, stamped parts, and stacking tolerances. That isn’t unique to SIG as there are many other makers from which I have multiple models and the triggers are rarely the same from model to model. I have no complaints about the IntelliFire and admit that I too was initially a little weary of a striker-fired pistol without an apparent mechanical safety device like a trigger dingus.
A hidden hero for many of my favorite pistols has come from DPM Systems Technologies who also has products for the P365. Their patented replacement recoil assembly uses three springs (the third spring is hidden within the guide rod) to progressively decelerate and accelerate the slide.
Three or four different main springs as well as two or three spacers (depending on handgun model) are included which allow you to tune the recoil assembly to your grip and ammunition choice. The big win for me has been when I tune to the point that the slide no longer bottoms out in rearward travel, where most felt recoil comes from, yet the slide doesn’t slam forward so hard that it causes muzzle dip.
That can be a bit of a process, but for avid shooters it’s well worth it. More information about that can be found in my videos exploring options. (Part 1 and introduces and Part 2 includes footage of range testing.)
Demonstrating how far the SIG P365 platform has evolved, my favorite configuration is using the FUSE’s 4.3″ slide, a DPM Systems Technologies recoil assembly tuned to almost maximum strength, and the Icarus Precision AIR grip module. The AIR grip is polymer, but includes the incredible traction and ergonomics of Icarus Precision’s aluminum grips.
That combination might be a bit big for some to use as a carry gun, but it makes for one heck of a quick-handling range or home defense gun while maintaining that P365 slimness that makes it easy to tuck away.
With so many build options, it’s easy to see how a SIG P365 can serve as your one handgun for everything from concealed carry to range master.