Sig P320 Build Planner: Parts, Fit and Prices
Modular 9mm built around a serialized fire control unit. Swap sizes freely. 48 parts from 11 brands, each checked for fit against the rest of your build, with prices compared across retailers.
Open the Sig P320 BuilderStart from a Complete Build
Three Sig P320 builds where every part already fits, from $644.94. Open one in the builder and swap anything you like.
What's in the Budget Sig P320
- Fire Control Unit: Sig Sauer P320 Fire Control Unit $159.99
- Grip Module: Sig Sauer Grip Module, Compact, Medium $49.99
- Slide Assembly: Sig Sauer P320 Compact Slide Assembly, 9mm $249.99
- Barrel: Sig Sauer P320 Barrel, Compact 3.9", 9mm $119.99
- Recoil Spring: Sig Sauer Recoil Spring Assembly, Compact $24.99
- Magazine: Sig Sauer P320 15-Round Compact, 9mm (OEM) $39.99
What's in the Best Value Sig P320
- Fire Control Unit: Sig Sauer P320 Fire Control Unit $159.99
- Grip Module: Sig Sauer X-Series Carry Grip Module $59.99
- Slide Assembly: Sig Sauer P320 M18 Slide Assembly, 9mm $379.99
- Barrel: Faxon P320 Compact 3.9" Flame Fluted, 9mm $174.99
- Recoil Spring: Sig Sauer Recoil Spring Assembly, Compact $24.99
- Optic: Sig Sauer Romeo1Pro 6 MOA $244.99
- Magazine: Mec-Gar P320 17-Round, 9mm $29.99
What's in the Premium Sig P320
- Fire Control Unit: Sig Sauer P320 X-Series Fire Control Unit $189.99
- Grip Module: Sig Sauer X-Series Full Grip Module $59.99
- Slide Assembly: Sig Sauer P320 XFull Slide Assembly, 9mm $399.99
- Barrel: Sig Sauer P320 Barrel, Full 4.7", 9mm $119.99
- Recoil Spring: Sig Sauer Recoil Spring Assembly, Full $24.99
- Optic: Sig Sauer RomeoX Pro $339.99
- Magazine: Sig Sauer P320 17-Round, 9mm (OEM) $41.99
Sig P320 Parts and Prices
Every Sig P320 part we list, cheapest first, with the lowest price we found (prices last checked Oct 5, 2026). The builder checks how each one fits with the rest of your parts.
Fire Control Unit
2 options, $159.99 to $189.99. The serialized chassis. Everything else is a swappable part.
Grip Module
8 options, $49.99 to $249.99. Sets grip length and dust cover length.
| Sig Sauer Grip Module, Compact, Medium Budget PickCompact · 9/.40/.357 · 15 rd mags | $49.99 at Sig Sauer (sample price) |
|---|---|
| Sig Sauer Grip Module, Carry, MediumCarry (full grip, compact dust cover) · 9/.40/.357 · 17 rd mags | $49.99 at Sig Sauer (sample price) |
| Sig Sauer Grip Module, Subcompact, SmallSubcompact · 9/.40/.357 · 12 rd mags | $49.99 at Sig Sauer (sample price) |
| Sig Sauer Grip Module, Full, Medium (.45 ACP)Full size · .45 ACP · 10 rd mags | $49.99 at Sig Sauer (sample price) |
| Sig Sauer X-Series Carry Grip Module Best ValueCarry (full grip, compact dust cover) · 9/.40/.357 · 17 rd mags | $59.99 at Sig Sauer (sample price) |
| Sig Sauer X-Series Full Grip ModuleFull size · 9/.40/.357 · 17 rd mags | $59.99 at Sig Sauer (sample price) |
| Wilson Combat P320 Grip Module, CarryCarry (full grip, compact dust cover) · 9/.40/.357 · Aggressive texture · 17 rd mags | $139.95 at Brownells (sample price) |
| Sig Sauer AXG Alloy Grip Module, Carry Premium PickCarry · Aluminum · 9mm · 17 rd mags | $249.99 at Sig Sauer (sample price) |
Slide Assembly
6 options, $249.99 to $399.99. Comes with sights and slide parts installed.
| Sig Sauer P320 Compact Slide Assembly, 9mm Budget PickCompact 3.9" · 9mm · No optic cut · SIGLITE sights | $249.99 at Sig Sauer (sample price) |
|---|---|
| Sig Sauer P320 Subcompact Slide Assembly, 9mmSubcompact 3.6" · 9mm · No optic cut | $259.99 at Sig Sauer (sample price) |
| Sig Sauer P320 Full Slide Assembly, .45 ACPFull 4.7" · .45 ACP · No optic cut | $279.99 at Sig Sauer (sample price) |
| Sig Sauer P320 Compact Slide Assembly, 9mm, Optic ReadyCompact 3.9" · 9mm · Optic ready · X-Ray3 sights | $299.99 at Sig Sauer (sample price) |
| Sig Sauer P320 M18 Slide Assembly, 9mm Best ValueCompact 3.9" · 9mm · Optic ready · Coyote | $379.99 at Sig Sauer (sample price) |
| Sig Sauer P320 XFull Slide Assembly, 9mm Premium PickFull 4.7" · 9mm · Optic ready | $399.99 at Sig Sauer (sample price) |
Barrel
6 options, $119.99 to $194.99. Length and caliber must match the slide.
| Sig Sauer P320 Barrel, Compact 3.9", 9mm Budget PickCompact 3.9" · 9mm | $119.99 at Sig Sauer (sample price) |
|---|---|
| Sig Sauer P320 Barrel, Full 4.7", 9mm Premium PickFull 4.7" · 9mm | $119.99 at Sig Sauer (sample price) |
| Sig Sauer P320 Barrel, Subcompact 3.6", 9mmSubcompact 3.6" · 9mm | $119.99 at Sig Sauer (sample price) |
| Sig Sauer P320 Barrel, Full 4.7", .45 ACPFull 4.7" · .45 ACP | $129.99 at Sig Sauer (sample price) |
| Faxon P320 Compact 3.9" Flame Fluted, 9mm Best ValueCompact 3.9" · 9mm · Match grade | $174.99 at OpticsPlanet (sample price) |
| True Precision P320 Compact Axiom Barrel, 9mmCompact 3.9" · 9mm · Match grade | $194.99 at OpticsPlanet (sample price) |
Recoil Spring
3 options, $24.99. Matched to slide length.
Optic
4 options, $244.99 to $339.99. Sig optic-ready slides use the Romeo1Pro / DeltaPoint footprint.
| Sig Sauer Romeo1Pro 6 MOA Best ValueRomeo1Pro footprint · Direct mount | $244.99 at Primary Arms (sample price) |
|---|---|
| Holosun HS407C X2RMR footprint · 2 MOA dot | $249.99 at Primary Arms (sample price) |
| Holosun HS507C X2RMR footprint | $299.99 at Primary Arms (sample price) |
| Sig Sauer RomeoX Pro Premium PickRomeo1Pro footprint · Larger window | $339.99 at OpticsPlanet (sample price) |
Magazine
5 options, $29.99 to $44.99. Should be at least as long as the grip.
| Mec-Gar P320 17-Round, 9mm Best ValueFull · 17 rd · 9mm | $29.99 at MidwayUSA (sample price) |
|---|---|
| Sig Sauer P320 15-Round Compact, 9mm (OEM) Budget PickCompact · 15 rd · 9mm | $39.99 at MidwayUSA (sample price) |
| Sig Sauer P320 17-Round, 9mm (OEM) Premium PickFull · 17 rd · 9mm | $41.99 at Sig Sauer (sample price) |
| Sig Sauer P320 12-Round Subcompact, 9mm (OEM)Subcompact · 12 rd · 9mm | $41.99 at Sig Sauer (sample price) |
| Sig Sauer P320 10-Round, .45 ACP (OEM)Full · 10 rd · .45 ACP | $44.99 at Sig Sauer (sample price) |
Weapon Light
3 options, $134.99 to $379.00. Must fit the frame's accessory rail.
| Streamlight TLR-7A500 lm · Glock and 1913 rail keys | $134.99 at Primary Arms (sample price) |
|---|---|
| Streamlight TLR-7 Sub, 1913 Short500 lm · Short 1913 rails | $145.00 at Brownells (sample price) |
| SureFire X300U-A1,000 lm · Universal and Picatinny mounts | $379.00 at Brownells (sample price) |
Holster
9 options, $64.99 to $74.99. Molded for one pistol size, with or without a light.
| Vedder LightTuck IWB, P320 SubcompactKydex IWB · Optic cut · Open bottom | $64.99 at Brownells (sample price) |
|---|---|
| Vedder LightTuck IWB, P320 CompactKydex IWB · Optic cut · Open bottom | $64.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 FullKydex IWB · Optic cut · Open bottom | $64.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Subcompact + TLR-7AKydex IWB · Carries TLR-7A · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Subcompact + X300Kydex IWB · Carries X300 · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Compact + TLR-7AKydex IWB · Carries TLR-7A · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Compact + X300Kydex IWB · Carries X300 · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Full + TLR-7AKydex IWB · Carries TLR-7A · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
| Vedder LightTuck IWB, P320 Full + X300Kydex IWB · Carries X300 · Optic cut · Open bottom | $74.99 at Brownells (sample price) |
Case
2 options, $54.97 to $109.95. Any pistol case fits; check length if you run a light or comp.
| Savior Equipment Specialist Double Pistol Case, 14"Soft · Two pistols · Mag pouches | $54.97 at Brownells (sample price) |
|---|---|
| Pelican 1170 Protector CaseHard · Watertight · Lockable | $109.95 at OpticsPlanet (sample price) |