Introduction
This manual provides essential instructions for the safe and proper use, maintenance, and care of your Sig Sauer P365 4.5mm Steel BB CO2 Air Pistol. Please read this manual thoroughly before operating the air pistol. Retain this manual for future reference.
Safety Information
WARNING: This is not a toy. Adult supervision is required. Misuse or careless use may cause serious injury or death. Always treat this air pistol as if it were loaded. Keep your finger off the trigger until ready to shoot. Always point the muzzle in a safe direction. Be aware of your target and what is beyond it. Always wear eye protection when handling or shooting this air pistol.
Proposition 65 Warning: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
Legal Disclaimer: You must be 18 years or older to buy any air gun or air rifle. Airguns or BB guns cannot be shipped to New York City and its boroughs (Manhattan, Brooklyn, Bronx, Queens, Staten Island, zip codes: 100xx-104xx, 110xx, 112xx-114xx, 116xx), the city of Philadelphia, PA, and Washington DC. Residents of Chicago, IL cannot buy CO2 powered rifles, pistols or revolvers directly from us. Residents of New Jersey can buy BB guns through a designated local gun store after acquiring an Airgun Permit.
Package Contents
Your Sig Sauer P365 Air Pistol package should contain the following items:
- Sig Sauer P365 4.5mm Steel BB CO2 Air Pistol
- 20-round BB Magazine
Setup
1. CO2 Cartridge Installation
- Ensure the air pistol is unloaded and the safety is engaged.
- Remove the magazine from the air pistol by pressing the magazine release button.
- Locate the CO2 cartridge compartment at the bottom of the magazine.
- Unscrew the CO2 cap using the provided Allen key or a suitable tool.
- Insert a new 12-gram CO2 cartridge into the compartment with the narrow neck facing upwards.
- Screw the CO2 cap back in firmly until the cartridge is pierced and sealed. Avoid overtightening to prevent damage to the seal.

Image: A 12-gram CO2 cartridge being inserted into the magazine base. The magazine is detached from the pistol.

Image: A 12-gram CO2 cartridge fully installed and secured in the magazine base with the cap tightened.
2. BB Loading
- With the magazine removed, pull down the BB follower spring until it locks into the notch at the bottom of the magazine.
- Insert 4.5mm steel BBs into the loading port at the top of the magazine. The magazine has a 20-round capacity.
- Release the follower spring gently to push the BBs into position.
- Reinsert the loaded magazine into the air pistol until it clicks securely into place.

Image: The 20-round magazine for the Sig Sauer P365 air pistol, ready for BB loading.
Setup Overview Video
Video: An official overview of the SIG SAUER P365 4.5mm Steel BB CO2 air pistol, demonstrating key features and setup steps. Provided by Pyramyd AIR.
Operating Instructions
1. Engaging and Disengaging Safety
The Sig Sauer P365 air pistol features a manual ambidextrous safety. To engage the safety, push the safety lever upwards until the red indicator is covered. To disengage the safety, push the lever downwards to expose the red indicator, signifying the pistol is ready to fire.
2. Firing the Air Pistol
- Ensure you are in a safe shooting environment and wearing appropriate eye protection.
- Aim the air pistol at a suitable target.
- Disengage the safety.
- Pull the trigger to fire. The semi-automatic action and full blowback metal slide will simulate the feel of its firearm counterpart.

Image: Side view of the Sig Sauer P365 air pistol, showcasing its compact design.

Image: Rear view of the Sig Sauer P365 air pistol, showing the green high visibility 3-dot fixed sights.
Product Overview and Operation
Video: A detailed overview of the Sig Sauer P365 4.5mm Air Pistol, including its features and operational aspects. Provided by Neil.
Maintenance
Regular maintenance ensures the longevity and optimal performance of your air pistol.
1. Cleaning
- After each use, wipe down the exterior of the air pistol with a clean, dry cloth to remove any dirt or debris.
- Periodically clean the barrel using a cleaning rod and appropriate cleaning patches.
2. Lubrication
- Apply a small amount of silicone-based airgun oil to moving parts, such as the slide rails and trigger mechanism, to ensure smooth operation.
- A drop of oil on the CO2 cartridge seal can help maintain its integrity and prevent leaks.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Air pistol does not fire or fires weakly. | Empty CO2 cartridge, improperly installed CO2, low CO2 pressure, BB jam. | Replace CO2 cartridge, ensure cartridge is fully pierced and sealed, clear any BB jams. |
| CO2 leaks from the magazine. | Damaged CO2 seal, loose CO2 cap, cross-threaded cap. | Apply a drop of oil to the CO2 seal, tighten the CO2 cap properly, inspect for damage and replace the magazine if necessary. |
| Slide does not cycle properly or return to battery. | Low CO2 pressure, lack of lubrication, obstruction. | Replace CO2 cartridge, lubricate slide rails, check for and remove any obstructions. |
| BBs are difficult to load. | Follower spring not fully retracted, BBs not aligned. | Ensure follower spring is locked down, load BBs one at a time carefully. |
Specifications
- Action Type: Semi-Auto
- Accessory Rail: SIG Rail
- Caliber: 4.5mm Steel BB (0.177)
- Optimal Pellet Weight Range: 5.0gr - 6.0gr
- Overall Length: 5.75 inches
- Trigger Weight: 4.25 lbs
- Velocity: Up To 300 fps
- CO2 Cylinder Size: 12gr
- Weight: 13 ounces
- Rounds: 20
- Frame Material: Alloy Steel, Metal
- Barrel Material Type: Metal
- Grip Type: Plastic
- Product Dimensions (L x W x H): 1" x 1" x 1"
Warranty and Support
This Sig Sauer P365 Air Pistol comes with a 2-Year Manufacturer Warranty. For warranty claims, technical support, or service inquiries, please contact Sig Sauer customer service directly. Refer to the official Sig Sauer website or product packaging for the most current contact information.