Setup: Byrna MISSION-4 Kit User Manual

Byrna MISSION-4 Kit

Introduction

The Byrna MISSION-4 Kit is a next-generation, less-lethal launcher engineered for maximum performance, safety, and reliability. Designed for home defense, property protection, and recreational use, this CO₂-powered launcher delivers non-lethal kinetic and chemical projectiles with precision and ease. With its robust construction, AR-15-style ergonomics, and high-capacity magazines, the Byrna MISSION-4 Kit stands out as a powerful tool for personal security and training.

Key benefits include fully pneumatic operation—no batteries or electronics required—ensuring operation in any environment. The durable magnesium receiver, integrated M-LOK shroud with quad Picatinny rails, and flip-up adjustable sights make it both user-friendly and customizable for tactical applications. Its dual-coupled magazines allow rapid switching between kinetic and chemical rounds, enhancing versatility in dynamic situations.

The Byrna MISSION-4 Kit is ideal for responsible adults seeking an effective, non-lethal self-defense solution. Its legal status as a less-lethal weapon means it is not a toy—purchases are restricted to those 18 and older. The kit typically retails in the $600–$800 range and is available through authorized dealers and the official Byrna website, with shipping to all 50 U.S. states.

Whether used for home defense, training, or recreation, the Byrna MISSION-4 Kit offers a compelling alternative to traditional firearms, combining advanced features, ease of use, and peace of mind for those prioritizing safety without sacrificing performance.

Detailed Specifications: Byrna MISSION-4 Kit

• Power Source: 88g CO₂ cartridge (required), no batteries or electronics
• Operation: Fully pneumatic, semi-automatic
• Velocity: Up to 365 feet per second (FPS), average 325 FPS
• Kinetic Energy: Maximum 18.5 Joules, average 14.5–14.7 Joules
• Effective Range: Up to 100 feet (longest of any Byrna launcher); law enforcement reports 39 ft on a 6” target and 65 ft on an 18” target
• Magazine Capacity: Dual coupled 19-round magazines (one black for kinetic rounds, one orange for pepper rounds)
• Shots per CO₂ Cartridge: 55–60 rounds, depending on conditions
• Receiver: Durable magnesium construction
• Rail System: AR-15 style M-LOK shroud with 4-sided Picatinny rails for accessories
• Safety: Two-position external selector switch (Safe/Fire)
• Charging Handle: Anodized orange aluminum
• Barrel: High-performance anodized orange with muzzle brake
• Length: Under 32 inches
• Warranty: 2-year manufacturer’s warranty

Compared to similar,r less-lethal launchers, the Byrna MISSION-4 Kit offers greater magazine capacity, longer effective range, and a more robust build, making it a top choice for users seeking a reliable, high-capacity solution.

GETTING STARTED

• Do not pressurize a partially assembled launcher.
• Read each step completely before performing the step.
• Review the image below to familiarize yourself with the location of features.
• NOTE: Carefully tighten all threaded parts when assembling, and do not over-tighten, as this may potentially strip the threaded parts. 

BARREL BLOCKING DEVICE INSTALLATION 

1. Place the barrel blocking device onto the Barrel and position the cord under the Charging Handle as shown.
2. Adjust the cord length retainer up to the back of the Charging Handle by pulling the cord through it until the retainer is snug against the back of the Charging Handle. Keeping the cord as tight as possible, leave just enough cord elasticity to remove the barrel blocking device for firing.
3. After the cord length is properly adjusted, lock the cord length by tying a knot in the cord against the back of the retainer as shown.
4. Before and after using the launcher, inspect the barrel blocking device. Replace the barrel blocking device if the device or cord is damaged, or if there is a loss of cord elasticity.
5. Clean the barrel blocking device with plain, warm water and store it out of sunlight in a dry area when not in use.

INSTALLING CO2 CARTRIDGE & BUTTSTOCK

WARNING: CO2 CARTRIDGE SAFETY

• When the CO2 pressure falls below a certain pressure, the Mission-4 will cease firing or may begin to sputter. If the Mission-4 is exposed to an increase in temperature, the pressure may increase enough for the Mission-4 to be able to regain the ability to fire.
• Use only Byrna authorized 88g or 90g CO2 cartridges in this device.
• Improper use, storage, or disposal of CO2 cartridges may result in property damage, serious personal injury, or death.
• Do not expose pressurized CO2 cartridges to temperatures exceeding 120°F.
• Keep all CO2 cartridges out of the reach of children.
• Keep exposed skin away from escaping gas when installing or removing the CO2 cartridge, or if the launcher or CO2 cartridges are leaking. Compressed CO2 gas is very cold and can cause frostbite under certain conditions.
  1. Put the Safety Selector Switch in Safe mode (page 7) and install the barrel blocking device (page 8). Put the  CO2 ON-OFF valve in the OFF position by sliding it to the rear. The e magazine from the launcher and check to make sure no projectile is in the breach.
  2. Point the barrel in a safe direction. Cock the launcher by pulling the Charging Handle all the way back. Always keep the launcher in the cocked position when installing a CO2 cartridge and whenever the CO2 cartridge is attached to the launcher. This will help prevent an accidental discharge.
  3. Lubricate the CO2 cartridge valve O-Ring with Byrna Certified Launcher Oil.
  4. Insert the CO2 cartridge into the back end of the launcher.
  5. Twist the CO2 cartridge clockwise into the CO2 cartridge adapter until it stops and is pierced.
  6. Install the CO2 buttstock by sliding it over the rear of the CO2 cartridge and securely tighten the buttstock to the CO2 cartridge using the inincluded/8” hex key.  DO NOT OVER-TIGHTEN

Use caution as the launcher is now capable of firing after you put the Safety Selector Switch in Fire mode and slide the CO2 ON-OFF valve forward to the ON position. 

If you do not hear the full CO2  cartridge engage, the pin valve could be too short or the pin valve seal may be damaged. 

MAINTENANCE & CLEANING

Basic maintenance should be performed every 500 shots, or as needed. The Mission-4 features a 2-year limited factory warranty that may be voided if unauthorized service is attempted, the device is modified, or used with unauthorized projectiles or unauthorized gas cartridges. 

WARNING
Always remove the O2 cartridge and magazine and clear the breach before performing any maintenance.

LAUNCHER MAINTENANCE

• To reduce the chance of an accidental discharge, follow the Unloading Your aqLauncher (on page 10) and CO2 Cartridge Removal (on page 10) before performing maintenance on your launcher.
• Eye protection must be worn.
• Do not disassemble the launcher, especially while it is pressurized.
• Do not pressurize a partially assembled launcher.
• Follow the warnings listed on the CO2 cartridge for handling and storage.
• Familiarize yourself with the instructions listed on the CO2 cartridge.
• Contact the CO2 cartridge manufacturer with any questions.
• Do not use any petroleum-based cleaning solvents.
• Do not use any cleaning solvents that come in aerosol cans.

NOTE: Petroleum-based products and aerosol products can damage your launcher’s O-rings.

CLEANING YOUR LAUNCHER
To clean the exterior of your launcher, use a damp towel to wipe off any powder residue, grease, and any debris.

BARREL CLEANING
To clean inside the barrel, remove the Magazine. Insert a barrel swab into the breech, going through the Magazine well. Pull the barrel swab through the barrel to remove powder residue or debris.

ALTERNATIVE BARREL CLEANING METHOD
You can also remove the barrel to pull the barrel swab through it.

Troubleshooting and Support: Byrna MISSION-4 Kit

LIMITED FACTORY WARRANTY

The Mission-4 personal security device is warranted by Byrna Technologies Inc., solely to the original retail purchaser, to be delivered free from factory defects in materials and workmanship, under normal use, for a period of two years from the original date of purchase. To obtain warranty coverage, the warranty holder must (i) provide proof of original purchase, and (ii) the defective device must be safely and securely packaged and shipped before the expiration of the warranty period to Byrna Technologies Inc.’s designated service center in accordance with instructions provided with the Return Merchandise Authorization. The buyer’s remedy under this warranty is limited, at the sole option of Byrna TTechnologies., to a refund or credit to the buyer of the price, or replacement of the defective device or other product. Byrna Technologies Inc. shall have the sole authority to determine if a claim is covered by this limited warranty.

EXCLUSIVITY OF WARRANTY AND LIMITATION OF REMEDIES
The remedy set forth above is the exclusive remedy for breach of the foregoing warranty. Except for the limited warranty expressly set forth above, Byrna Technologies Inc. makes no express or implied warranties or representations with respect to any Byrna products, including any warranty of merchantability, warranty of fitness for a particular purpose, or warranty against infringement of intellectual property rights of a third-party.  Buyers and owners are prohibited from making any warranty or representation regarding any Byrna product that is inconsistent with the express, limited factory warranty set forth above. To the extent that applicable law does not permit for a disclaimer of express or implied warranties, Byrna Technologies Inc. hereby limits all express and implied warranties to two (2) years from the date of the original retail purchase.

PROHIBITED USES, ALTERATION, VOIDABILITY OF WARRANTY
Owners should not attempt to take apart or repair the Mission-4, or use it with any unauthorized or incompatible accessories, projectiles, or gas cartridges.  Any alteration, abuse, misuse, neglect, or attempt to disassemble the device or use or install any unapproved third-party product may void the warranty.  The warranty also may be voided if the Mission-4 or any accessory or other product is improperly handled, stored, or shipped.

END USER’S ASSUMPTION OF RISK
Before use, the user shall determine the suitability of the product for its intended use, read and understand all instructions, warnings, and safety considerations provided in this manual, take all reasonable precautions to ensure its safe use, and assume all risks and liabilities in connection with the purchase, possession, and discharge of the Mission-4.  Byrna Technologies Inc. shall have no liability nor shall it assume any obligation to the purchaser of any Byrna device or any third party for any special, non-compensatory, consequential, indirect, incidental, statutory, or other damages whatsoever, including, without limitation, punitive damages,  lost profits , lost opportunities, lost revenue, loss of consortium, or other damage loss or injury whatsoever, regardless of the form of action and regardless of whether it sounds in contract, negligence, statutory or common law liability, or otherwise, known or unknown, even if fore-seeable or explicitly informed,  in any amount greater than the amounts paid by buyer to Byrna Technologies Inc. for the products, unless due to the gross negligence or willful misconduct of Byrna Technologies Inc..  The limitations set forth above shall be deemed to apply to the maximum extent permitted by applicable law and notwithstanding the failure of the essential purpose of any limited remedies.  Any buyer who does not agree to this assumption of risk may return the products purchased, in their original packaging, unused, and in original condition within 7 days of purchase.

Preventive Measures

• Always store the launcher and CO₂ cartridges in a cool, dry place.
• Regularly inspect and clean the barrel and magazines.
• Use only Byrna-approved projectiles and CO₂ cartridges.

Warranty and Support

The Byrna MISSION-4 Kit comes with a 2-year warranty covering manufacturer defects. For issues beyond basic troubleshooting, visit the official Byrna website for product manuals, safety data sheets, and contact information for customer support[8].

Contact Byrna Support: Use the contact form on the official Byrna website or call their customer service line for direct assistance with your MISSION-4 Kit.

Pros & Cons: Byrna MISSION-4 Kit

Advantages

• High Capacity: Dual 19-round magazines provide rapid reloading and versatility between kinetic and chemical rounds.
• Long Range: Effective up to 100 feet—longest of any Byrna launcher—making it suitable for various defensive scenarios.
• Durable Build: Magnesium receiver and AR-15 ergonomics ensure reliability and comfort during extended use.
• No Batteries Required: Fully pneumatic operation means no reliance on electronics, ideal for emergencies.
• Easy to Customize: Quad Picatinny rails and M-LOK compatibility allow for a wide range of accessories.
• Legal Alternative: Provides a less-lethal option for home defense, with fewer legal restrictions than firearms in many areas.

Disadvantages

• CO₂ Dependent: Requires 88g CO₂ cartridges, which must be kept on hand and can be affected by temperature.
• Heavy: The robust construction adds weight compared to smaller, pistol-style launchers.
• Price: Higher cost than entry-level,, less-lethal options, though justified by features and build quality.
• Limited Projectile Types: Only compatible with Byrna projectiles, limiting ammunition choices.

Compared to alternatives, the Byrna MISSION-4 Kit offers superior capacity and range, but users should weigh the need for portability and ongoing CO₂ costs against its advanced features.

Customer Reviews and Testimonials

User feedback for the Byrna MISSION-4 Kit highlights its reliability, ease of use, and effectiveness as a less-lethal home defense tool. Many customers praise the launcher’s robust construction, customizable rail system, and the convenience of dual magazines for switching between kinetic and pepper rounds. The launcher’s consistent performance and long effective range are frequently cited as major advantages.

Some users note that the launcher is heavier than expected, and a few mention the need to keep extra CO₂ cartridges on hand for extended use. Star ratings typically range from 4 to 5 stars, with most recommending the Byrna MISSION-4 Kit for those seeking a high-capacity, non-lethal self-defense solution.

Common praises include the launcher’s intuitive controls, quick assembly, and the peace of mind it provides. Criticisms are mostly limited to the weight and the ongoing cost of CO₂ and projectiles. Overall, the Byrna MISSION-4 Kit is highly recommended for responsible adults prioritizing safety and performance in a less-lethal platform.