Best Sig Sauer P320 upgrades – 2020 Part 1 of 2: The Upper Half
The Sig Sauer P320 has been, without a doubt, one of the more exciting pistol platforms introduced in the past decade. This is, measured based on military and law enforcement adoption, popularity within the competitive communities, and the vast aftermarket support for the platform.
We are watching the popularity rise as it's continually ranked in our top 5 most searched for products on the Rainier Arms website. With that said, we thought we'd make a list of all of the various aftermarket parts for this very popular firearm. And with Sig Sauer's latest announcement of their FCU (Fire Control Unit) program, it's only going to get more popular.
The SIGnificance of the FCU Program
It's apparent now that Sig Sauer has not only recognized the importance of having the support of these aftermarket products, but they are proactively reaching out to some of the best out there to bridge the gap and open a dialogue to better support aftermarket companies. It was at this meeting that they announced a new program where they would be selling the FCU or Fire Control Unit, which is the serialized part of the gun. You could essentially put any size grip, slide, etc. with the FCU. Almost similar to how you can build up an AR15 from various manufacturers and parts, you can now do the same with the Sig P320. Rather than buy a stock P320, you could just buy JUST the FCU, and build a Sig Sauer' ish P320. This is hands down one of the smartest moves I have seen a manufacturer to recognize a trend and find a way to support it and partner with these companies. We will see even more companies hop on board with this.
With that said, let's discuss all of the upgradeable parts for the P320. So hit the bathroom and grab some snacks, because this rabbit hole is deep. Let's start at the top!
SLIDES
It is easily one of the more popular options as changing the slide is one of the more impactful changes you can make to both the aesthetics and function of your firearm. You could also decide if you want to hop on the Mini Red Dot train, and have your slide pre-cut to accept any of the more popular Red Dot Sights available for pistol use.
We did a blog on some great options for Mini Red dots and the WHY, you can read here….
But the quick summary and pro are for having a mini red dot sight:
- Improve Accuracy
- Improve speed
- Both Eye Open shooting
- Lowlight
The Con's:
- More expense.
- Requires additional training to be proficient at.
- It's battery operated.
So this should be your first decision, to Red dot or not to red dot. I have always said it's better to have and not need, than need and not have. So even if you don't have money for a red dot right now, most all MRD sight cut slides have a "plate" that goes in place of the red dot, so you could continue to shoot and use iron sights on your gun until you decide to go into the dark side and buy a red dot sight.
Other aspects to think about for the slide option that's also popular are the various "cuts" for the gun to lighten the slide and offer front cocking serrations to you can pull off that smooth press check with no effort.
Here are a few of the top-selling slides we carry:
Full-Size P320 Slides:
NORSSO SIG SAUER P320C VECTOR RMR SLIDE - BLACK NITRIDE $436.05
GREY GHOST PRECISION SIG SAUER P320 FULL-SIZE SLIDE V1 $412.75
ZEV TECHNOLOGIES Z320 X-FULL OCTANE SLIDE W/ OPTIC CUT $399
Compact P320 Slides:
GREY GHOST PRECISION SIG SAUER P320 COMPACT SLIDE V1 $402.19
GREY GHOST PRECISION SIG P320 COMPACT V2 SLIDE $402.19
NORSSO SIG SAUER P320C VECTOR RMR V2 SLIDE $436.05
FULL-SIZE P320 SLIDES
NORSSO SIG SAUER P320C VECTOR RMR SLIDE - BLACK NITRIDE

The Vector is a Sig Sauer P320 Compact/carry compatible aftermarket slide that Norsso manufactures in-house at their shop in Las Vegas. They start with a 17-4 stainless steel billet and CNC mill the critical dimensions creating a slide blank. To achieve the ability to modify the exterior of the slide, they leave mass in the forward area of the slide near the muzzle. This allows them to remove more material in other areas of the slide for porting, customization, and enhanced serrations. Without the redesigned slide blank, you run the risk of an unreliable firearm from large amounts of slide milling. Heavily modifying the factory compact P320 slide is generally frowned upon in the Sig community. For this reason and the standard forward serrations that are provided from the factory, Norsso designed an aftermarket solution.
GREY GHOST PRECISION SIG SAUER P320 FULL-SIZE SLIDE V1

The adoption of the P320® platform by the U.S. Military, as well as many Law Enforcement agencies, professional lead farmers, competition shooters, and firearm instructors, led to the development of a new line of GGP aftermarket slides. After all, the P320's ability to be custom-tailored to the individual user's preferences in grip length, grip size, as well as slide length and sight radius are all highly desirable features. Why stop there, when you can have even more customization options when upgrading to a drop-in GGP320 slide.
ZEV TECHNOLOGIES Z320 X-FULL OCTANE SLIDE W/ OPTIC CUT - GREY

ZEV Technologies Octane Slide for the SIG Sauer P320 XFull offers improved glare resistance and grip with our signature slide channeling serrations. Trijicon RMR compatible optics cut comes standard on the XFull Octane Slide.
Compact P320 Slides
GREY GHOST PRECISION SIG SAUER P320 COMPACT SLIDE V1

The adoption of the P320® platform by the U.S. Military, as well as many Law Enforcement agencies, professional lead farmers, competition shooters, and firearm instructors, led to the development of a new line of GGP aftermarket slides. After all, the P320's ability to be custom-tailored to the individual user's preferences in grip length, grip size, as well as slide length and sight radius are all highly desirable features. Why stop there, when you can have even more customization options when upgrading to a drop-in GGP320 slide.
GREY GHOST PRECISION SIG P320 COMPACT V2 SLIDE

Just like the Grey Ghost Precision GGP17/19 and SPG43 slides, these GGP320 slides offers enhanced aesthetic features, increased grip serrations, and an improved coating without compromising function. Grey Ghost Precision also took their hybrid MRDS optic cut and added a third option, the SIG ROMEO1. Now you have to option to use a ROMEO1 as well as a Trijicon RMR or Leupold DeltaPoint Pro right out of the box without using bulky adapter plates that only raise the optic further above the bore axis. The GGP320 is a drop-in install that comes with all the enhancements that professional handgun shooters have come to expect from Grey Ghost Precision.
NORSSO SIG SAUER P320C VECTOR RMR V2 SLIDE

The Vector is a Sig Sauer P320 Compact/carry compatible aftermarket slide that norsso manufactures in-house at their shop in Las Vegas. They start with a 17-4 stainless steel billet and CNC mill the critical dimensions creating a slide blank. To achieve the ability to modify the exterior of the slide, Norsso leaves mass in the forward area of the slide near the muzzle. This allows Norsso to remove more material in other areas of the slide for porting, customization, and enhanced serrations. Without the redesigned slide blank, you run the risk of an unreliable firearm from large amounts of slide milling. Heavily modifying the factory compact P320 slide is generally frowned upon in the Sig community. For this reason and the standard forward serrations that are provided from the factory, Norsso designed an aftermarket solution.
BARRELS
What better way to improve accuracy and complement your slide better than an aftermarket barrel. The barrels available now for the Sig P320 from an aftermarket standpoint come in either threaded or non-threaded for the use of compensators and suppressors. Barrels can also come in various finishes that help improve lock up and provides better durability. Overall, the consideration of using an aftermarket barrel is very high. Here are some of our best selling barrels for P320.
Best Barrels for the P320
GREY GHOST PRECISION P320 COMPACT BARREL - BLACK NITRIDE $177.59
AGENCY ARMS SIG P320 COMPACT PREMIER LINE BARREL – TIN > $300
KILLER INNOVATIONS SIG P320C VELOCITY NON-THREADED BARREL $209.99
L2D COMBAT PRECISION MATCH SIG SAUER P320 COMPACT $213.75
ZEV TECHNOLOGIES Z320 X-FIVE PRO BARREL - DLC $189.05
AGENCY ARMS SIG P320 COMPACT PREMIER LINE BARREL – DLC $300
FAXON FIREARMS SIG SAUER P320 FULL SIZE FLAMED BARREL $204.25
GREY GHOST PRECISION P320 COMPACT BARREL - BLACK NITRIDE

Specifications:
- 416R Gun Barrel Quality Stainless Steel
- Match Grade drop-in barrel
- Threaded Barrels are 1/2 x 28" TPI and include an O-Ring and Thread Protector
- Threaded Barrels are optimized for suppressor use
- Final dimension of +/- 0.003" for consistent accuracy
- SAAMI spec. 9mm Match chambers
- 1:10 twist rate
- SIG® P320 Compact
- Black Nitride Finished
AGENCY ARMS SIG P320 COMPACT PREMIER LINE BARREL – TIN

Specifications:
- Large Agency "A" Raised within the Machined Top Area of the lockup.
- Large "AGENCY" Deep machined on the Port Side of the lockup.
- (6) Flats machined around the circumference of the barrel.
- Polished Feed Ramp to decrease friction
- Polished Crown (on non-threaded models)
- Compatibility: SIG P320 Compact/X-Compact
KILLER INNOVATIONS SIG P320C VELOCITY NON-THREADED BARREL

Barrel Specs:
- Material: 416R
- Chamber: 9MM Luger
- Twist Rate: 1:10
- Rifling: Single Point Cut with "SPT" Technology
Non-Threaded Barrel:
- Weight: 3.3 OZ
- Length: 3.862" O.A.L.
L2D COMBAT PRECISION MATCH SIG SAUER P320 COMPACT

Barrel Features:
- 3.9" Barrel Length
- Made in the USA
- U.S. Sourced 416R Chromium Stainless Steel
- 38-42 Rockwell Hardness (HRc) Ensures Lengthy Service Life
- Improved Critical Dimensions For Superior Lockup, Fitment, and Performance
- Manufactured to Precision Tolerance Requirements for Match Grade Accuracy and Consistency
- Cut Rifled Bore
- 1:10 R.H. Twist Rate
- Custom Designed Double Honed Precision Match Polished Bore
- Fully Supported SAMMI Spec Match Grade Polished Chamber
- Proprietary Target Crown Aids in Projectile Stability
- Polished Feed Ramp for Added Reliability
- 8 Flute "Spear Tip" Design to Aid in Heat Dissipation and Reduce Weight
ZEV TECHNOLOGIES Z320 X-FIVE PRO BARREL – DLC

ZEV Technologies PRO Barrels offer a streamlined hood design that incorporates the ZEV logo slashes and caliber marking.
- Designed for the Sig Sauer P320 X-Five
- Black DLC coating
AGENCY ARMS SIG P320 COMPACT PREMIER LINE BARREL – DLC

Specifications:
- Large Agency "A" Raised within the Machined Top Area of the lockup.
- Large "AGENCY" Deep machined on the Port Side of the lockup.
- (6) Flats machined around the circumference of the barrel.
- Polished Feed Ramp to decrease friction
- Polished Crown (on non-threaded models)
- Compatibility: SIG P320 Compact/X-Compact
FAXON FIREARMS SIG SAUER P320 FULL SIZE FLAMED BARREL - THREADED NITRIDE

- 416-R Stainless - Only the best steels for durability, longevity, and accuracy.
- 9mm SAAMI Chambers - Superior accuracy with complete SAAMI compatibility & boring reliability.
- Tighter Tolerances - Drop-in, yet better fitment and lockup.
- Conventional Rifling - Fully compatible with cast bullets
- 11 Degree Target Crown
Technical Specifications:
- Handgun Type: Sig Sauer P320 FULL Size
- Barrel Caliber: 9mm
- Barrel Profile: Flame Fluted, Drop-In
- Barrel Material: 416-R Stainless Steel
- Barrel Twist: 1:10
- Muzzle Thread: 1/2x28 TPI
- Crown: 11-degree Target Crown
- Rifling Method: Button Rifled, Fully Stress Relieved
- Rifling Type: Conventional
- Inside Finish: Salt Bath Nitride
- Outside Finish: Salt Bath Nitride
Other P320 Upper Parts to consider
There are a few other items to consider for your P320 build from sights, compensators, and small parts kits. Here are a few of those things.
SPRINGER PRECISION P320 9MM SHORTY COMPENSATOR (1/2 X 28) $85
SPRINGER PRECISION SIG P320 9MM OPEN COMPENSATOR (1/2 X 28) $95
AGENCY ARMS SIG P320 DUAL PORT COMPENSATOR - BLACK $100
TYRANT DESIGNS T-COMP SIG SAUER P320 $85.45
NIGHT FISION SIG SAUER GLOW DOME TRITIUM NIGHT SIGHTS SET $107
SIG SAUER P320 OEM SLIDE COMPLETION KIT $79.99
P320 Upper Parts
SPRINGER PRECISION P320 9MM SHORTY COMPENSATOR (1/2 X 28)

These compensators are specifically designed for the Sig P320 and our Barsto aftermarket barrel with compensator threading, in 1/2 x 28. Will NOT work with the SIG factory threaded barrels. Designed to also work with most factory ammunition. Made from USA sourced aluminum and matte black anodized for a lightweight, long-lasting compensator to tame muzzle flip and soften recoil. .852oz
**THIS COMP IS NOT FOR USE WITH SIG FACTORY THREADED p320 BARRELS
SPRINGER PRECISION SIG P320 9MM OPEN COMPENSATOR (1/2 X 28)

These compensators are specifically designed for the Sig P320 and our Barsto aftermarket barrel with compensator threading, in 1/2 x 28. For use with factory +p ammunition or 9mm major ammunition. Will NOT work with the SIG factory threaded barrels. Made from USA sourced aluminum and anodized for a lightweight, long-lasting compensator to tame muzzle flip and soften recoil. 1.072oz
**THIS COMP IS NOT FOR USE WITH SIG FACTORY THREADED P320 BARRELS
AGENCY ARMS SIG P320 DUAL PORT COMPENSATOR - BLACK

The Agency Arms 419 Compensator is a high performing and uniquely designed component for Sig P320 pistols. The 419 Compensator is precision machined from high-quality aluminum and features a seamless 1/2 "-28 thread design. The 419 Compensator helps to disburse gases away from the shooter creating enhanced control over the firearm. The 419 Compensator is an excellent choice for anyone serious about upgrading their Sig pistol!
TYRANT DESIGNS T-COMP SIG SAUER P320

The Tyrant Designs CNC Sig Sauer P320 Compensator, known as the P320 T-Comp, dramatically reduces muzzle rise and sensed recoil, allowing much quicker target re-acquisition. Compatible with ½-28 threaded barrels, our compensator requires no modification to your Sig P320, and once assembled fits most open-ended holsters. The T-Comp works on all Sig P320 configurations and will function using almost any grain ammunition.
NIGHT FISION SIG SAUER GLOW DOME TRITIUM NIGHT SIGHTS SET

Night Fision Glow Dome Night Sight Set with Front + "Square" Rear
Phosphorescent Orange/Yellow Front Glow Dome with Green Tritium + Black Rear Glow Domes with Green Tritium
Fits P-Series Pistols with #8 Front Sights
SIG SAUER P320 OEM SLIDE COMPLETION KIT

Sig Sauer P320 OEM Slide Completion Kit
Includes:
- Sig Sauer P320 Extractor
- Sig Sauer P320 Extractor Pin
- Sig Sauer P320 Extractor Spring
- Sig Sauer P320 Extractor Pin Plus
- Sig Sauer P320 Striker Assembly
- Sig Sauer P320 Rear Slide Cap
That should pretty well cover some of the better options for your P320 build for the upper half. Stay tuned next week as we talk about the lower half of the P320 build to discuss triggers, mag wells, and grip modules, oh my!