SIG P365 Upgrades: Top Barrels, Grips And More

We discuss some of the best aftermarket parts for upgrading a SIG P365, one of America’s most popular carry pistols.

SIG Sauer’s P365 is one of the most popular carry guns in the country. Since it was introduced, it has quickly outpaced the sales for other guns in the same category and has inadvertently created something of an arms race all its own.

Why? Well, it’s extremely tiny, but it has an onboard capacity of 10+1 rounds standard. Not only did this completely upset the balance of power in the micro-compact world, but it also set the stage for a reinvention of what we know when it comes to accuracy and reliability in the size class. It could be said that the P365 completely redefined the carry gun.

Modular Madness

However, we as a people rarely leave well enough alone. In many cases, this hubris results in “upgrades” that are anything but. We’ve seen it time and time again—some type of gimmick becomes all the rage but ends up offering no real benefit for the shooter in the end.

I remember that feeling of coming home with a blank slate whenever I picked up a new Glock, Beretta or 1911. I can’t tell you the number of times I’ve permanently altered something because of the words of an instructor I saw on YouTube, or the creeping sensation that if I didn’t have the right stippling on my grip I was at a serious disadvantage.

Most guns on the market today are fine just as they are. Even though many people regard the standard Glock sights, for example, as merely dovetail protectors, they’re, in fact, quite functional and perfect for most end uses. Yet, it’s very hard to find somebody at competitions, carry classes or even the range who shoots with stock sights. The culture of “customizability” has infiltrated every aspect of shooting, and up until now, you had to take a gamble on your gun’s value if you wanted to increase certain aspects of its performance.

It took the shooting public quite a while to realize the potential of SIG’s modular handgun systems. The original attempt to add such a design wasn’t well received, and I wonder as I write this how many shooters even remember the P250, the progenitor of the P320. While not a reinvention of the handgun wheel, the P250 was a step in the right direction when it came to treating a user to a customizable pistol that could be quickly and easily converted between full-size and subcompact on one internal chassis. This design was eventually discontinued.

However, the stage was set and, while not a groundbreaking design in its own years of production, the P250 is owed the credit of being an important design. In the following years, the P320 and subsequent P365 have dominated the national scene. Unlike some others, SIG has embraced the aftermarket and even endorsed the use of third-party parts on their guns. While this might seem insignificant in the world of modular everything, this is really the first time in the commercial history of arms production that small shops have the ability to supply a major manufacturer with custom parts … and have those parts assembled out of the factory for shipping to the customer.

P365 Barrels

My top recommended brands for P365 barrels are True Precision and Faxon. I’ve shot these brands extensively with zero issues. They are, in my direct experience, slightly better in terms of on-paper accuracy than SIG factory, Grey Ghost Precision and ZEV.

How much better? Well, True Precision and Faxon average about 1 inch at 10 yards for five shots, the others 1.5 to 2 inches. At 25 yards, True Precision offers the best across the board, about 3.5 inches for five shots of any given load. The sights on the P365 aren’t exactly fine, but they’re precise enough. The sight radius is the real limiting factor, and at a point you just can’t expect to be shooting dimes with a micro 9mm.

Luckily for you, all the above brands are readily available online. These barrels are great, but the stock P365 barrel is very accurate. Most of these barrels are a cosmetic upgrade, and if you want added function, you’re looking at a threaded model. I’d consider the cost of the threaded models to be worth it simply if you want to buy yourself an additional 50 fps on most loads.

P365 Grip Modules

Because the serialized part of the P365 is the internal chassis (fire control unit), you’re free to swap out your grip style as much as you like. Polymer versions are pretty nice and can be had for relatively cheap. If you want to practice your own stipple patterns, SIG sells OEM grip modules. If you mess up, you aren’t out a gun. SIG makes these in several styles, including 10- and 12-round sizes, and in a few colors.

Aluminum modules are all the rage now, and there are a growing number of companies that offer them. Icarus Precision has several variations encompassing any finished size and barrel length currently made. These are very well-made pieces; however, I find them to be too slender in the grip and have some uncomfortable bumps on the trigger guard. You might feel differently. SIG offers Icarus models on the P365 build studio.

Mischief Machine is another company that’s hitting the aluminum module market quite hard. These are very clean designs that mimic the shape of the stock unit. They work with all of my normal P365 holsters. Available in both a single-piece and with grip panels, the Mischief Machine designs are very well made and have some nice, subtle performance-enhancing touches, such as a 4140 steel recoil lug and bushings for the grips. Not only does this grip module have a tangible impact on accuracy, but it’ll also likely outlast the rest of the parts with just how well it is made.

Wilson Combat makes an excellent polymer grip module that’s an affordable, functional upgrade over the SIG stock module. At a retail price of about $65, it offers quite a bit, including an undercut trigger guard, optional weight channels to balance the gun, an extended beavertail and comfortable texturing. For the money, this is a very good P365 upgrade, and it’s a fraction of the cost of an aluminum module.

Optics

Optics are starting to appear on all types of pistols these days, and SIG was one of the first companies to offer optically equipped pistols from the factory. Grey Ghost makes a great optics-ready slide that’s at the top of my list. I’ve put many rounds down range with one, and it was a clean and well-made upgrade. If you prefer something a bit flashier, ZEV has their Octane slide with RMSC optics cut, and it has about as much serration as the Emerson knives I carry. While it may appear to be overkill, the P365 is a very small gun, and extra traction never hurts.

Last on the list is the True Precision Axiom. Like the others, it’s a drop-in proposition and allows for a couple different types of optics to be mounted. I wasn’t a huge fan of the cosmetics and the ports cut in the sides—while it might a be a moot point, I don’t like places where lint can collect, but to each his own.

Small P365 Upgrades & Parts

The nice thing about the P365 is that you can order most of the small parts direct from SIG. They have a parts shopper on their website that’s very helpful. A growing number of companies are also producing small parts, such as triggers and enhanced springs. But, at that point, you might just want to invest in a SIG FCU and build up your gun around it.

The P365 is a relatively easy gun to work on—though there are more things going on in that small gun than you’re probably aware of. If you want to make some changes, make sure you educate yourself or watch enough tutorial videos on how to navigate the inner workings.

Editor’s Note: This article originally appeared in the 2022 Everyday Carry special issue of Gun Digest the Magazine.

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