P320 Modularity Options
Since its introduction, the SIG Sauer P320 (and all of its many and ever-growing sub models M17, M18 to name a few) has been known for its ease of customization and modularity. However, the amount of information that is out there can be overwhelming. The P320 is offered in many different calibers, barrel lengths, grip sizes (and lengths)
Calibers:
9mm, 40 &W, .357 Sig, .45 ACP, 10mm Auto
Barrel (Slide Lengths):
The slides themselves are actually longer however they are referred to by the barrel lenghts
3.6” (Sub-Compact & X-Compact) (9mm, 40 S&W, .357 Sig)
Good luck finding a 3.6” 357 Barrel anymore (Dont know if Sig ever offered it in a 45 for the P320)
3.9” (Compact, Carry, M18, X-Carry) (9mm, 40 S&W, .357 Sig & .45 ACP)
4.7” (Fullsize, M17, X-Full) (9mm, 40 S&W, .357 Sig & .45 ACP)
5.0” (X-5, X-Ten) (9mm & 10mm Auto)
There are 3 basic Fire Control units aka FCU’s:
- 9mm, 40 S&W & .357 Sig (Standard FCU)
-This is the most common to find and comes in all the standard P320’s The X-Series, Legion, AXG’s are also the same FCU. The Custom Works FCU is the same however it has a Tin “Gold” Coating
-For the most part all the internal parts function the same (Yes there are different triggers, Trigger Bar’s, Slide catches (will be covered in another article)
-This same FCU is used for the X-Ten per SIG with one part changed to properly function with the X-10 grip/ Mags (The 45 Takedown Safety Lever) - M17, M18 & Other Manual Safety FCU’s:
-These are basically the same as the standard FCU’s however they have a special notch cut into them to allow the Manual safety lever, Spring and detent to fit and function. There are 4 different parts in these vs the regular FCU’s
-Manual Safety Trigger Bar
-Manual Safety Lever Right
-Manual Safety Lever Left
-Manual Safety Lever Spring
-Manual Safety Lever Detent
INSERT Picture here - The Manual safety on thee FCU’s can be removed and the Safety Lever pin installed in place and they will function as normal (in a grip Module without the Manual Safety Cut)
- .45 ACP FCU:
-All the same parts except for:
-Takedown Safety Lever
-Slide Catch (However in my experience they all work in the 45)
-This means you can use and P320 Trigger in the 45 FCU
-From my experience and many others (online) the 45 FCU is the “Universal” FCU as it can be used in 9mm, 40 S&W, 357 Sig as well as 45 and now 10mm
**You Must use the proper magazines and grip modules as you CANNOT put 45 & 10mm magazines in 9/40/357 grip modules and vice versa. The 45 & 10mm magazines are wider and longer (as 45 and 10mm are longer rounds than 9/40/357)
Grip Modules (Where the modularity comes to life):
This is where the P320 really starts to come alive as there are hundreds of possibilities offered and they seem to just keep growing.
SIG offers a grip modules in Black and Coyote Polymer (Also used to offer White and Olive Drab Green) in “regular” as well as X-Series, TXG (Tungsten infused polymer X-Grip) which is a Gray Color and the newest is the AXG (Aluminum X-Series Grip Module) Which is offered in Black, Coyote and Titanium Finishes. The AXG Grip Modules also have panels that can be changed to further customize ability.
There are also aftermarket options (none pictured for this article) from Wilson Combat, P80, Mirzon, Icarus Precision to name a few. There are also many companies that offer custom work to grip modules like laser Stippling/ grip enhancement, Stippling, Custom paint/ Cerakote.
Grip Modules (Where the modularity comes to life):
Regular Grips:
- -Sub Compact (Smallest Grip Offering from SIG)
- -Small (no Rail)
- -Medium (accessory Rail – No Longer Produced)
- -3.6” Slide is flush with the end of the Grip Module
- -3.9” Slide is has a .3” overhang from the end of the Grip Module
- -Magazines: 12rd (9mm) 10rd (40 S&W & 357 Sig) 6rd (.45 ACP) flush fit with the grip, a finger extension magazine is also offered
- -15rd (9mm), 13rd (40 & 357) and larger magazines will fit and function however they will stick out.
