DCA/Rainier Arms Sig P320: Unsurpassed Custom Performance

I love my job. Not only do I work from home, but gun companies also send me fun products to test. I generally like most of them, though I’ve gotten a few lemons. But I occasionally get something that I absolutely love. Sometimes, it’s the cool factor, but it has to perform, too. However, occasionally, I’ll get a cool gun whose performance just knocks my socks off. The DCA/Rainier Arms Custom Sig P320 X-Carry is one of those rarities.

The DCA/Rainier Arms Sig P320

I don’t normally gush in an article’s introduction. I try not to gush at all, even when I like something. But this gun exceeded my already high expectations based on what I saw at TriggrCon 2024.

I wasn’t able to shoot the gun at TriggrCon, but Rainier Arms arranged to send me one for testing. For the record, I don’t get to keep it, and it will have been returned by the time this review is published. Read on to see why I like it so much.

The DCA/Rainier Arms Sig Sauer Custom P320 X-Carry. — (Photo by Rainier Arms)

Sig’s modular P320 platform is ripe for customization. The DCA/Rainier Arms model takes advantage of that while not going overboard. Each upgrade makes sense and aims to maximize the firearm’s performance and enhance the shooter’s capabilities.

Let’s look at the slide and grip frame separately.

P320 Slide Enhancements

The DCA Slide Milling Package features deep, multi-tiered front and rear cocking serrations. Those serrations also cover the slide’s top between the breech and the front sight. Slide ports under the front sight aid with airflow, while also slightly lightening the pistol. The serrations and ports also look good, especially with the gold titanium-nitrided (TiN) barrel.

The Rainier Arms logo is milled into the slide, denoting the two companies’ partnership. In addition, the slide is also DLC (Diamond-Like Carbon) coated for maximum protection and durability.

The Slide Milling Package features deep, multi-tiered front and rear cocking serrations. — (Photo by Rainier Arms)

A dovetailed, blacked-out, serrated rear sight and tritium fiber-optic front sight make for a stellar sight picture. The milled Trijicon RMR optic cut negates the need for an optic plate and allows the shooter to use the iron sights should the optic fail. An ambidextrous slide stop rounds it out.

The Grip Frame

DCA/Rainer pistol frames come with DCA’s custom Cerakote. My test pistol is in OD Green. It looks sharp with the black side and grip panels and the gold TiN barrel. DCA replaced the grip panels with their proprietary “Brain” pattern textured grip. A single glance explains the name.

It does indeed look like a brain’s surface and wraps all the way around. The texture cuts are deep and provide outstanding purchase, while not being sandpapery, which I love. I think the grip’s positivity is as good as any pistol I’ve handled. There are no interchangeable backstraps, as with all P320s.

DCA replaced the grip panels with their proprietary “Brain” pattern textured grip on the DCA/Rainier Arms Sig P320 X-Carry. — (Photo by Rainier Arms)

The trigger guard is undercut for a high grip, and its front is textured if you like that. The prominent beavertail all but eliminates slide bite. Correspondingly, the P320 magazine release is reversible.

The gun retains the P320’s modularity with Sig’s serialized fire control unit. It also features Sig’s X-Series straight trigger.

Running the DCA-Rainier Arms P320 X-Carry

I will say up front that this DCA/Rainier pistol is the most accurate handgun, out of the box, that I’ve ever tested. I usually have to learn where a gun is hitting at 7 yards or 10 yards, but this one was point-of-aim/point-of-impact right away. I tore up the dueling tree at 10 yards with my first magazine. That doesn’t usually happen.

Our friends at Ammo-to-Go and Global Ordnance provided us with several ammunition loads for this test:

124-grain Sellier & Bellot FMJ (100 rounds)
124-grain Igman FMJ (100 rounds)
115-grain Magtech FMJ (50 rounds)
115-grain Federal American Eagle FMJ (100 rounds)
124-grain Federal Hydra-Shok JHP (15 rounds)

The pistol was 100 percent reliable through those 365 rounds.

The DCA/Rainier pistol was 100 percent reliable through those 365 rounds. All reliably rang steel and held tight groups, with the 124-grain S&B perhaps a bit more accurate than the rest. But only just.

I can confidently say that this gun is more accurate than I am. The gun’s accuracy was so apparent from the start that it drew immediate exclamations from me and my co-tester. Again, that usually doesn’t happen.

Shootability of the Custom P320

The Sig P320 doesn’t have the best grip I’ve ever run, but it’s comfortable and fills my hand. I like the DCA “Brain” textured grip panel. I think it improves the Sig grip considerably. The controls are positive and easy to reach.

The Sig X-Series Flat-Faced Trigger is very good. There’s a slight take-up before a definite wall and a crisp break 30 percent lighter than the standard P320 trigger. I also have the Sig flat trigger on my P365XL, and I love it. DCA does not do trigger work, so it is a Sig trigger.

The DCA/Rainier Arms Sig P320 X-Carry is among the easiest-shooting handguns the author has ever run.

Some guns are more comfortable and pleasant to shoot than others. I also understand how that perception is very subjective. But this DCA/Rainer P320 is among the easiest-shooting handguns I’ve ever run. It just feels natural.

The sights acquire easily, and it’s dead accurate. I love tritium front sights. I have one on my P365XL, which is my primary carry gun. They draw my eyes just as a red dot does. This sight does that, and I think it contributes to how well I shoot it. It’s a nice feature.

But the optic cut beckoned. So, I later installed a Meprolight MPO-F red dot, which is one of my favorite optics. It also fits the RMR footprint, so there’s that. The direct cut allows a low co-witness with the iron sights, which is really nice. I have some plate-mounted optics that don’t allow co-witnessing or make it so razor-thin that it’s all but useless.

The author installed a Meprolight MPO-F red dot, which is one of his favorite optics.

Once I zeroed the optic, the gun was just as accurate, though I think I like it better without. Did I mention how much I love tritium front sights? But everyone is different, so you do you. The point is that you have two good choices here.

Custom Handguns

I have a love-hate relationship with custom handguns. They often look great, though I think some go overboard. The custom slide work is sometimes so extensive that the gun itself requires major retuning to make it run properly. I also question the necessity of some of the work. But who am I to say that folks shouldn’t buy such things as long as they’re safe?

DCA guns are fine-tuned, but the customization seems targeted. I haven’t spoken to anyone at DCA about it, but it just looks that way to me. Even my non-technical mind easily comprehends why the work was done and why it enhances my shooting experience. I don’t see anything that I think is just fluff.

And, like most custom projects, it makes the gun look good. I always say that I like good-looking guns, even though looks don’t mean a thing if the gun doesn’t work. I think most of us are like that. But custom guns can get very expensive very fast, hence my skepticism. I generally conclude that my skill level doesn’t require a custom gun, especially at those prices.

This DCA/Rainier Arms gun costs more than a standard Sig P320 X-Carry.

This DCA/Rainier gun costs more than a standard Sig P320 X-Carry. Of course, it does. It’s even a little more than the X-Carry Legion, but not much. However, at the time of this writing, the DCA/Rainier gun is on sale for just a bit more than a standard X-Carry.

The way this gun operates, shoots, and handles, I think it’s probably worth the extra money. I may end up with one myself sometime because I’ve enjoyed it so much. And I never really thought I’d buy a custom semi-auto handgun.

Final Thoughts

I already said that I love this pistol. It would immediately have a spot in my carry rotation if it belonged to me. Some guns, even ones I like, are inevitably relegated to the safe.

I can only shoot one gun at a time, especially with my job. Not this gun. It would get the work, and would probably put one of my other regular guns on the bench. Times change and this gun is that capable.

Custom handguns may or may not be your thing. If so, or if you’re thinking about it, give Danger Close Armament a look. You can deal with them directly, or you can look at their Rainier Arms collaborations, which go beyond this particular model. You can also buy slides and barrels separately.

I can only speak for the gun I tested, but I hope to do more with Danger Close in the future. I’m optimistic that their other products perform as well as this one did.

For more information, please visit RainierArms.com.