5.56 NATO M855 62gr FMJ (Green Tip)
- ✓Useful 62gr baseline
- ✓May be restricted at some ranges

Use this guide to match ammo to your rifle setup and mission without getting lost in internet lore. Start with safety (chamber markings), then pick a bullet type and weight that your barrel twist can stabilize.
Chamber compatibility: 5.56 NATO and .223 Wylde chambers fire both cartridges interchangeably. A .223 Rem chamber will also handle 5.56 in any modern production barrel without issue, despite what older forum posts claim: SAAMI pressure differences are minimal and well within modern metallurgy margins.
Match bullet weight to twist rate: 1:7 twist handles 69-77gr. 1:9 twist best with 55-62gr. Short barrels need faster twist for heavier bullets.
Pick projectile by mission: FMJ for training volume, OTM for accuracy, bonded soft point for barriers, lead-free copper where required.
Pick your mission and rifle details to get a simple, safe starting point for what to buy and test.
Affordable, consistent, and reliable in your magazines.
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Best for training volume. Buy consistency: the same lot, the same brand, and enough to confirm reliability in your magazines.
Best for accuracy and wind performance. Common in 69–77gr bullets; these usually prefer faster twist rates.
Best when you want consistent performance through common barriers. Prioritize reputable duty-style loads and test feeding in your magazines.
Best when lead-free is required. Copper bullets can be longer for weight, so twist rateTwist Rate[Barrel]How many inches it takes the rifling to complete one rotation (e.g., 1:7 means one twist every 7 inches). Faster twists (lower numbers) stabilize heavier bullets better. stability matters.
5.56 is a small, fast projectile. It does not rely on mass to be effective. It relies on velocity. Understanding how different projectiles behave at impact is critical to choosing the right load for your application.
M193 and similar FMJ loads fragment when they hit soft tissue above roughly 2,700 fps. The jacket separates from the core and creates multiple wound channels. This is highly velocity-dependent: as distance increases and velocity drops below the fragmentation threshold, FMJ becomes an ice pick that punches straight through with minimal energy transfer. Barrel length matters here. A 10.3" barrel launching M193 at 2,800 fps has a much shorter fragmentation window than a 16" barrel at 3,200 fps.
Soft point, hollow point, and OTM designs all expand on impact, creating a larger wound channel and transferring more energy to the target. OTMs like MK262 (77gr Sierra MatchKing) are functionally equivalent to soft points in terminal performance: the open tip initiates expansion just as reliably. Bonded projectiles like Speer Gold Dot hold their weight together through barriers (glass, drywall, sheet metal) and still expand reliably on the other side. Unbonded hollow points can shed their jacket on barrier strikes and underperform. For defensive use, bonded is the standard through barriers; OTM and soft point are interchangeable without them.
M855 (green tip) has a steel penetrator ahead of a lead core. Rather than fragmenting cleanly, it tends to yaw (rotate sideways) in tissue after several inches of penetration. Terminal performance is inconsistent: sometimes it yaws early and is devastating, sometimes it sails straight through. This unpredictability is why most professionals have moved to purpose-built defensive loads like M855A1 or commercial bonded options.
The common thread across all 5.56 terminal performance is velocity. Below roughly 2,500 fps, most projectiles lose their ability to fragment or expand reliably. This is the fundamental planning factor: your barrel length determines muzzle velocity, distance determines impact velocity, and impact velocity determines what the bullet actually does. Short barrels and long distances both push you toward loads that are less velocity-dependent, like bonded soft points, which expand mechanically rather than relying on hydraulic forces.
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Purchasing through these links may generate a commission at no extra cost to you. Always confirm chamber markings and manufacturer guidance before firing 5.56 NATO loads.
Purchasing through these links may generate a commission at no extra cost to you. This section is informational only—follow local laws and get training appropriate to your needs.
Purchasing through these links may generate a commission at no extra cost to you. Always verify hunting regulations in your area.
Purchasing through these links may generate a commission at no extra cost to you. Always verify compliance requirements in your area.
Essential accessories to round out your setup
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Avid shooter with 9+ years of experience including competition shooting. Built 10+ AR-pattern rifles and several handgun platforms for home defense, competition, and suppressed night shooting.
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