Winchester M855 5.56x45mm NATO FMJ Ammo: Precision, Performance, and Unmatched Reliability

For competitive shooters, tactical trainers, and dedicated firearms enthusiasts seeking ammunition that delivers consistent performance under a variety of conditions, the Winchester M855 5.56x45mm NATO FMJ ammunition stands out as a premier choice. This isn't just another box of rounds; it's a meticulously engineered cartridge built to military specifications, designed to offer superior accuracy, reliability, and unique capabilities for serious firearm owners. If you've ever asked "What's the best ammunition for AR-15 training?" or "Which 5.56 round offers excellent penetration?", the Winchester M855 is a definitive answer.

This detailed overview will explore why Winchester M855 is often cited by experts and preferred by users for everything from precision target shooting to dynamic training exercises. We'll delve into its unique projectile design, the benefits of its military specification, and how it can elevate your shooting experience. Available exclusively at DEGuns, this ammunition combines Winchester's century-long legacy of quality with the specific performance characteristics demanding shooters require.

Understanding the Winchester M855 5.56x45mm NATO FMJ Cartridge

The Winchester M855 is not merely a 5.56mm round; it is a direct descendant of ammunition designed for military operations, specifically adhering to the M855 military specification. This means it incorporates a distinct 62-grain Full Metal Jacket (FMJ) projectile, globally recognized as the SS109 "Green Tip" bullet. This designation is crucial for understanding its performance characteristics and why it's a popular choice among those who demand consistency and specific terminal performance from their ammunition.

Key Features and Design Excellence

Every aspect of the Winchester M855 ammunition is crafted to meet rigorous standards, ensuring optimal performance from your 5.56 NATO chambered firearms.

• Winchester WM855CP SKU: Identifies this specific Winchester product, ensuring you receive the authentic military-specification M855 ammunition. This SKU is your assurance of quality and consistency from one of the most trusted names in the industry.
• 5.56 NATO Caliber: Designed specifically for 5.56x45mm NATO chambers, ensuring proper fit, feeding, and reliable extraction in compatible rifles and carbines. While it can often be fired in .223 Remington chambers, understanding the differences between 5.56 NATO and .223 REM is crucial for safety and optimal performance. Always ensure your firearm is rated for 5.56 NATO ammunition when using M855.
• 62 Grain Full Metal Jacket Projectile: The standard weight for this military-spec round, offering a balance of velocity, stability, and trajectory. The Full Metal Jacket design ensures reliable feeding and prevents lead fouling in the barrel.
• SS109 Light Armor Piercing Green Tip Projectile: This is the hallmark of M855 ammunition. The "green tip" signifies the steel penetrator component within the projectile. Unlike typical lead-core FMJ rounds, the SS109 features a lead core with a hardened steel penetrating tip located at the front of the bullet, beneath the copper jacket. This design enhances its ability to penetrate light barriers and offers distinct ballistic properties.
• M855 Military Specification: Adherence to military specifications means this ammunition is manufactured to the same exacting standards demanded by armed forces. This ensures consistent quality, reliability, and predictable performance, making it an ideal choice for serious training and tactical applications.
• Lead Core with Steel Penetrating Tip: The internal construction of the SS109 projectile is key to its "light armor piercing" capability. The steel tip, designed to penetrate certain light barriers, differentiates it significantly from standard M193 55-grain FMJ ammunition. This makes it particularly effective for specific target types and training scenarios.
• Brass Cased: The use of high-quality brass casings ensures smooth feeding and extraction, contributing to the overall reliability of the ammunition. Brass cases are also highly desirable for reloaders due to their durability and ability to withstand multiple reloading cycles.
• Non-Corrosive Powder/Primers: This vital feature means the ammunition utilizes modern propellants and primers that will not cause corrosion or damage to your firearm's internal components over time. This reduces the need for immediate, rigorous cleaning after every range session and helps preserve the longevity of your valuable firearms.
• Reloadable: For shooters who enjoy custom loading or want to maximize the value of their ammunition, the Boxer-primed, brass casings of the Winchester M855 are fully reloadable, offering significant cost savings over time.
• Boxer Primed: Standard Boxer primers are used, which are common and easily accessible for reloaders. This is a key advantage for those who wish to reuse their spent casings.
• Consistent Accuracy: Winchester's commitment to quality manufacturing processes results in ammunition that delivers tight groups downrange. This consistency is paramount for both competitive shooters striving for precision and for trainers who need reliable feedback on their shooting mechanics.
• Reduced Barrel Fouling: The precise manufacturing and quality components minimize the build-up of residue within your barrel, leading to cleaner operation and less frequent cleaning cycles, which in turn helps maintain barrel longevity and accuracy.
• Made in the USA: Manufactured in the United States, this ammunition supports domestic industry and often implies adherence to stringent quality control standards.
• Annealing (Shoulder and Neck Discoloration) is Normal for Military Specification Cartridges: It's common to observe discoloration around the shoulder and neck of M855 casings. This is a result of the annealing process, a heat treatment used to soften the brass and prevent cracks during the manufacturing process. It's a sign of proper manufacturing for military-spec rounds, not a defect.
• Uses: Target Shooting, Training, and Plinking: This ammunition excels in a variety of recreational and practical shooting applications. Its consistent performance makes it ideal for honing skills at the range, participating in tactical drills, or simply enjoying a session of plinking.
• 30 Rounds on Stripper Clips and a Loading Tool (Magazine Spoon): Many Winchester M855 packages come with rounds conveniently pre-loaded onto stripper clips, accompanied by a loading tool. This greatly speeds up the process of loading magazines, a significant advantage during high-volume training sessions or when preparing for events where quick reloads are beneficial.

Ballistics and Performance Insights

The performance of Winchester M855 is characterized by its excellent velocity and energy, particularly at closer ranges, while maintaining effective ballistics out to moderate distances.

• Muzzle Velocity: With a formidable muzzle velocity of 3060 feet per second (ft/s), this ammunition delivers a flat trajectory and rapid target engagement at common shooting distances. This speed contributes to its inherent accuracy and responsiveness.
• Muzzle Energy: Generating 1289 foot-pounds (ft-lbs) of energy at the muzzle, the Winchester M855 packs a significant punch, indicative of its power and effectiveness.
• Primer Style: Centerfire: Utilizes the reliable and universally recognized centerfire ignition system, ensuring consistent primer strike and dependable cartridge ignition.

Why the "Green Tip" Matters: Safety and Application

A crucial aspect of the SS109 "Green Tip" projectile is its enhanced penetration capabilities. While not considered "armor-piercing" in the legal sense for civilian sales, its steel penetrator tip allows it to defeat certain light barriers that standard FMJ rounds might not.

Caution: Will Shoot Holes Through Steel Targets. This is an extremely important warning for all users. Due to the steel penetrator, shooting M855 ammunition at common steel targets (like those designed for pistol rounds or standard rifle FMJ) can cause significant damage to the targets, create dangerous ricochets, and pose a severe safety hazard to shooters and bystanders. Always ensure your range allows M855 ammunition and use appropriate, rated steel targets (e.g., AR500 steel or higher, at safe distances) when utilizing this round. Failure to observe this caution can lead to serious injury or property damage. If you are unsure, err on the side of caution and use standard FMJ rounds.

This characteristic makes M855 particularly suitable for training scenarios involving specific types of barriers or for those seeking ammunition that can reliably penetrate certain materials within a controlled environment, such as approved ballistic gel testing or specific military-style targets. It’s an essential round for understanding how different projectile designs interact with various mediums.

Who Benefits from Winchester M855?

Winchester M855 is an excellent choice for a variety of users who prioritize performance, reliability, and military-spec quality:

• AR-15 Owners and Enthusiasts: Given its design for 5.56 NATO chambers, it's a natural fit for the most popular rifle platform in America.
• Tactical Training Participants: For drills that require consistent cycling, reliable feeding, and a true military-spec feel, M855 is invaluable.
• Sport Shooters: Whether engaging in static target practice or dynamic shooting sports, the consistent accuracy and dependable performance help shooters refine their skills and achieve better results.
• Preppers and Stockpilers: Its military specification and widespread use make it a popular choice for those building an ammunition reserve, knowing they have a proven and reliable product.
• Those Seeking Penetration Capabilities: For specific, approved uses where the enhanced penetration of the steel tip is desired, the M855 is the go-to round.

Comparing M855 to Other 5.56/.223 Ammunition

Understanding the M855's place in the 5.56/.223 ecosystem is key to making an informed choice.

• M855 (62-grain SS109) vs. M193 (55-grain FMJ): The primary difference lies in the projectile. M193 is a standard 55-grain lead-core FMJ, designed for maximum velocity and fragmentation upon impact in soft tissue. M855, with its 62-grain weight and steel penetrator, sacrifices some velocity for enhanced barrier penetration. For general plinking and range use where steel targets are involved, M193 is often a safer and more economical choice. For specific tactical training or understanding barrier performance, M855 excels.
• 5.56 NATO vs. .223 Remington: While often interchangeable in 5.56 NATO chambered firearms, there are subtle differences in pressure and chamber dimensions. 5.56 NATO generally operates at higher pressures and has slightly looser chamber specifications. It is always safe to fire .223 REM in a 5.56 NATO chamber. However, firing 5.56 NATO ammunition (like M855) in a rifle chambered only for .223 Remington can be dangerous due to potential overpressure issues. Always verify your firearm's chambering.

Long-Term Value and Storage

Investing in high-quality ammunition like Winchester M855 is a sound decision for any responsible firearm owner. The non-corrosive components ensure a long shelf life when stored properly in cool, dry conditions. Its reloadable brass casings also add to its long-term economic value, allowing enthusiasts to extend the utility of their purchase significantly. For those who engage in high-volume shooting, the convenience of stripper clips and a loading tool can't be overstated, transforming the tedious process of magazine loading into a quick and efficient task.

Why Choose Winchester M855 from DEGuns?

When seeking top-tier ammunition like the Winchester M855, sourcing from a reputable dealer is paramount. DEGuns provides a trusted platform for acquiring this military-specification ammunition, ensuring authenticity, competitive pricing, and reliable service. As a dedicated firearms and ammunition retailer, DEGuns understands the needs of serious shooters and offers this premium Winchester product to meet those demands. Whether you're stocking up for future training, preparing for a competition, or simply seeking dependable rounds for your AR-15, DEGuns is your exclusive destination for Winchester M855.

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Winchester M855 5.56x45mm NATO FMJ Ammo Specifications

Specification	Detail
UPC	020892228863
SKU	WM855CP
Primer Style	Centerfire

Winchester M855 5.56x45mm NATO FMJ Ammo Ballistics: Velocity & Energy

Distance (yards)	Velocity (fps)	Energy (ft-lbs)
Muzzle	3060	1289
100	2876	1069
200	2529	800
300	2285	719
400	2055	581
500	1809	466

Winchester M855 5.56x45mm NATO FMJ Ammo Ballistics: Trajectory

Distance (yards)	Trajectory Short Range (in)	Trajectory Long Range (in)
150		1.5
200	-3	0
300	-11.4	-7.5
400	-26.6	-22.9
500		-49.4