Training · 62gr FMJ
5.56 NATO M855 62gr FMJ (Green Tip)
- ✓Useful 62gr baseline
- ✓May be restricted at some ranges
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AR-155.56 NATO.223 RemBallistics
5.56 Ammo Selection 2026: Match Your Load to Barrel Length & Mission
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.
Assumes knowledge of
AR-15 Barrel Length 2026->Quick Answer: TL;DR: Quick Ammo Selection
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.
>5.56 ammo finder
Pick your mission and rifle details to get a simple, safe starting point for what to buy and test.
LIVE55–62gr
5.56 ammo finder
Pick your mission and rifle details to get a simple, safe starting point for what to buy and test.
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Affordable, consistent, and reliable in your magazines.
2Rifle Setup(optional details refine results)
3Special Requirements
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55–62grRecommendation Ready
Training / range default
FMJ / bulk
- • Buy enough of one load to validate function (magazines + bolt hold-open) before stocking deep.
- • Value ammo is fine if it runs in your rifle; avoid switching lots constantly.
Results update automatically as you adjust settings above
Safety notes
- • Confirm your barrel's chamber marking (on the barrel itself). When in doubt, follow the barrel manufacturer's guidance.
Setup notes
- • If you don't know your twist rate, start with 55–62gr for training, then test 69–77gr if you want match performance.
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Projectile types (what you're really buying)
FMJ / bulk
Best for training volume. Buy consistency: the same lot, the same brand, and enough to confirm reliability in your magazines.
OTM / match
Best for accuracy and wind performance. Common in 69–77gr bullets; these usually prefer faster twist rates.
Bonded soft point
Best when you want consistent performance through common barriers. Prioritize reputable duty-style loads and test feeding in your magazines.
Solid copper (lead-free)
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.
Terminal effects: what happens on impact
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.
Fragmentation
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.
Expansion
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.
Yaw & tumble
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.
Velocity threshold
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.
Training · 55gr FMJ
PMC Bronze .223 Rem 55gr FMJ
- ✓Good baseline for reliability testing
- ✓Easy to find across retailers
$10.99
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Training · 55gr FMJ
Federal American Eagle .223 55gr FMJ
- ✓Widely stocked training option
- ✓Good for confirming POI vs other 55gr loads
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Training · 5.56 pressure
IMI 5.56 NATO M193 55gr FMJ
- ✓Common reference load for 55gr performance
- ✓Pairs well with general-purpose zeros
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Purchasing through these links may generate a commission at no extra cost to you. Always follow local laws and age requirements, and verify shipping restrictions for your area.
Match · 75gr
Hornady 75gr BTHP Match
- ✓Common heavy match option
- ✓Works well in many 1:8 and 1:7 barrels
$25.49
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Match · 77gr OTM
IMI Razor Core 5.56 77gr OTM
- ✓Common 77gr benchmark load
- ✓Great place to start for 1:7–1:8 rifles
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Match · 77gr OTM
Black Hills 77gr OTM
- ✓Premium match-grade consistency
- ✓Excellent for precision rifles
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Match · 69gr SMK
Federal Gold Medal .223 69gr Match
- ✓Mainstream match-grade option
- ✓Good for 1:8 barrels
$30.69
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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.
Bonded · 62gr
Federal Tactical Bonded 62gr
- ✓Designed for barrier handling
- ✓62gr weight plays well with many twist rates
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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.
Varmint · 55gr polymer-tip
Hornady V-MAX 55gr
- ✓High accuracy reputation
- ✓Designed for varmint use
$27.99
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Varmint · 55gr
Nosler Ballistic Tip 55gr (.223)
- ✓Common varmint bullet family
- ✓Good accuracy and terminal consistency on small game
$43.49
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Purchasing through these links may generate a commission at no extra cost to you. Always verify hunting regulations in your area.
Lead-free · copper
Barnes VOR-TX 62gr TSX
- ✓Well-known lead-free option
- ✓Often chosen for hunting compliance
$43.89
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Lead-free · copper
Federal Trophy Copper .223/5.56
- ✓Mainstream lead-free hunting option
- ✓Useful for compliance-focused ammo bins
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Purchasing through these links may generate a commission at no extra cost to you. Always verify compliance requirements in your area.
5.56/.223 Ammo FAQ
▶Can I shoot 5.56 NATO in a .223 Rem chamber?
Yes, any modern production barrel chambered in .223 Rem will handle 5.56 NATO without issue. The SAAMI pressure differences between the two are minimal and well within modern metallurgy margins. This was a legitimate concern decades ago with older firearms, but it is largely overblown today. That said, 5.56 NATO and .223 Wylde chambers are dimensionally optimized for both cartridges, so they remain the best choice if you plan to shoot a mix regularly.
▶What grain bullet should I use for my twist rate?
1:7 twist: Optimized for 69-77gr bullets, but stabilizes 55gr adequately. 1:8 twist: Versatile, handles 55-77gr well. 1:9 twist: Best with 55-62gr, may not stabilize 77gr. 1:12 twist: Limited to 55gr and lighter. When in doubt, 62gr M855/XM855 works in most twist rates.
▶What is the best 5.56 ammo for home defense?
Bonded soft points like Speer Gold Dot 64gr or Federal Fusion 62gr offer consistent expansion through barriers while limiting overpenetration. Hornady TAP 75gr is another quality option. Avoid FMJ for defense: it overpenetrates without reliable expansion. Test your chosen load in your rifle for reliability before relying on it.
▶What is the difference between M193 and M855?
M193: 55gr FMJ at ~3,200fps. Lighter, faster, fragments well at close range but loses effectiveness past 200 yards. M855 (green tip): 62gr with steel penetrator core at ~3,000fps. Better barrier penetration and longer effective range, but the steel tip can cause ricochets and some ranges ban it.
▶Is steel case ammo bad for AR-15s?
Steel case ammo (Wolf, Tula) is fine for training but has trade-offs: harder extraction can accelerate chamber wear, lacquer coatings may gum up chambers, and accuracy is typically worse than brass. It won't damage your rifle, but expect more cleaning and slightly reduced barrel life. Many ranges prohibit it due to fire risk from bimetal jackets.
▶What is the best ammo for accuracy/precision shooting?
77gr OTM loads like Black Hills MK262, Federal Gold Medal Match 77gr, or Hornady 73gr ELD-M offer excellent accuracy. These require 1:7 or 1:8 twist barrels. For 1:9 twist, try 69gr Sierra MatchKing loads. Match ammo costs $1-2/round, save it for zeroing and precision work, use bulk FMJ for training.
▶What brand of 5.56 is best?
For training, Federal XM193/XM855, Winchester USA, and IMI are reliable bulk options. For precision, Black Hills, Federal Gold Medal Match, and Hornady Match deliver consistent accuracy. For defense, Federal HST, Speer Gold Dot, and Hornady TAP are proven performers. Choose based on your mission and budget: consistency within a brand matters more than chasing 'the best' label.
▶What's better, 55gr or 62gr?
55gr (M193) is faster, fragments reliably at close range, and is ideal for 1:9 or faster twist rates. 62gr (M855) has better wind performance, penetrates barriers more effectively, and extends usable range. For general training and defensive use, 62gr is more versatile. For lightweight barrels or slower twist rates, stick with 55gr. Both work, pick based on barrel twist and primary use case.
▶What 5.56 ammo do Navy Seals use?
Navy SEALs primarily use MK262 Mod 1, a 77gr Open Tip Match load manufactured by Black Hills Ammunition. It offers superior accuracy, better wind performance, and effective terminal performance out to extended ranges compared to M855. Civilian equivalents include Black Hills 77gr OTM and Federal Gold Medal Match 77gr, both require 1:7 or 1:8 twist barrels for proper stabilization.
Complete Your Build
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ABAuthor
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.
9+ years shooting experienceCompetition shooterBuilt 10+ AR-pattern rifles
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