How do 5.56 ballistics differ by load type?
The tables compare M193, M855, and 77gr OTM by velocity (feet per second), energy (foot-pounds), drop (distance below the zeroed line of sight), and wind drift (sideways movement in a crosswind).
All data below uses factory ammunition from a 16" carbine barrel (1:7 twist) unless noted. Real-world velocities vary by barrel length, lot, and temperature. Trajectory is zeroed at 50/200 yards — the standard AR-15 battlesight zero, meaning the bullet crosses your line of sight at 50 yards on the way up and again at 200 yards on the way down.
Measured comparison: With the 16-inch barrel and 50/200-yard zero used below, the 77gr OTM has less drop and wind drift than M193 or M855 at 400–600 yards. These trajectory figures do not establish interchangeability in barrier or terminal performance.
Pricing tied to this data: See current 5.56 NATO ammo prices for live cost-per-round on M193, M855, and 77gr OTM across tracked retailers, plus cheapest 5.56 right now and .223 Remington pricing for chamber-compatible alternatives. For how 5.56 compares against every other tracked caliber, see the ammo price index and the cheapest calibers to shoot rankings.
M193 — 55gr FMJ
The original 5.56 NATO load. Light, fast, and widely available.
| Distance | Velocity | Energy | Drop (50/200 zero) | Wind drift (10mph) |
|---|---|---|---|---|
| Muzzle | 3,050 fps | 1,135 ft-lbs | — | — |
| 100 yards | 2,750 fps | 924 ft-lbs | +1.5" | 0.8" |
| 200 yards | 2,470 fps | 745 ft-lbs | 0" (zero) | 3.4" |
| 300 yards | 2,210 fps | 596 ft-lbs | −7.2" | 8.0" |
| 400 yards | 1,960 fps | 469 ft-lbs | −21.3" | 15.0" |
| 500 yards | 1,730 fps | 365 ft-lbs | −43.8" | 24.8" |
| 600 yards | 1,520 fps | 282 ft-lbs | −77.0" | 38.2" |
M193's velocity falls with distance; the table shows 2,470 fps at 200 yards and 2,210 fps at 300 yards. Its ballistic coefficient (BC ~0.243) is lower than the 77gr OTM's, so it sheds velocity more quickly in this comparison.
M855 — 62gr FMJ w/ steel penetrator
A 62gr load with a steel-tipped penetrator.
| Distance | Velocity | Energy | Drop (50/200 zero) | Wind drift (10mph) |
|---|---|---|---|---|
| Muzzle | 2,970 fps | 1,213 ft-lbs | — | — |
| 100 yards | 2,700 fps | 1,004 ft-lbs | +1.7" | 0.7" |
| 200 yards | 2,440 fps | 820 ft-lbs | 0" (zero) | 3.2" |
| 300 yards | 2,200 fps | 666 ft-lbs | −7.8" | 7.6" |
| 400 yards | 1,970 fps | 534 ft-lbs | −22.8" | 14.2" |
| 500 yards | 1,750 fps | 421 ft-lbs | −46.5" | 23.4" |
| 600 yards | 1,550 fps | 330 ft-lbs | −81.2" | 35.8" |
M855 is marginally slower at the muzzle than M193 (the 7-grain weight increase isn't fully offset by the charge). Trajectory is very similar. The steel penetrator was designed to penetrate the Soviet steel helmet at 600 meters — it doesn't meaningfully improve terminal performance on soft tissue and can actually reduce it by penciling through without fragmenting.
77gr OTM (Mk262 / Sierra MatchKing)
The precision and special operations load. Heavy-for-caliber with a high BC.
| Distance | Velocity | Energy | Drop (50/200 zero) | Wind drift (10mph) |
|---|---|---|---|---|
| Muzzle | 2,750 fps | 1,293 ft-lbs | — | — |
| 100 yards | 2,560 fps | 1,121 ft-lbs | +2.0" | 0.6" |
| 200 yards | 2,380 fps | 969 ft-lbs | 0" (zero) | 2.4" |
| 300 yards | 2,210 fps | 836 ft-lbs | −7.0" | 5.7" |
| 400 yards | 2,050 fps | 718 ft-lbs | −20.0" | 10.6" |
| 500 yards | 1,890 fps | 611 ft-lbs | −40.0" | 17.4" |
| 600 yards | 1,740 fps | 518 ft-lbs | −68.0" | 26.4" |
The 77gr OTM's higher BC (0.372 vs 0.243 for M193) corresponds to more retained velocity in these tables. At 600 yards, it carries 518 ft-lbs versus M193's 282 ft-lbs, and the stated wind drift is 31% lower.
Requires 1:8 or faster twist to stabilize (most modern ARs are 1:7).
How does barrel length affect 5.56 velocity?
The original M16 used a 20" barrel. The M4 carbine uses 14.5". Most civilian AR-15s use 16" (the legal minimum without an NFA tax stamp). Barrel length significantly affects 5.56 velocity.
| Load | 10.3" (Mk18) | 14.5" (M4) | 16" (civilian) | 20" (M16) |
|---|---|---|---|---|
| M193 55gr | 2,650 fps | 2,900 fps | 3,050 fps | 3,240 fps |
| M855 62gr | 2,570 fps | 2,830 fps | 2,970 fps | 3,100 fps |
| 77gr OTM | 2,400 fps | 2,620 fps | 2,750 fps | 2,900 fps |
5.56 NATO was designed for a 20" barrel. Every inch you cut costs roughly 25–30 fps. The biggest practical impact is on M193's fragmentation threshold — from a 10.3" barrel, M193 drops below the ~2,700 fps fragmentation velocity by 50–75 yards. From a 20" barrel, it stays above that threshold past 150 yards.
In this table, the 20-inch barrel gives 77gr OTM 150 fps more muzzle velocity than the 16-inch barrel. The table does not establish accuracy or terminal performance.
How much do the three loads drop at distance?
Zeroed at 50/200 yards from a 16" barrel:
| Distance | M193 (55gr) | M855 (62gr) | 77gr OTM |
|---|---|---|---|
| 50 yards | 0" (zero) | 0" (zero) | 0" (zero) |
| 100 yards | +1.5" | +1.7" | +2.0" |
| 200 yards | 0" (zero) | 0" (zero) | 0" (zero) |
| 300 yards | −7.2" | −7.8" | −7.0" |
| 400 yards | −21.3" | −22.8" | −20.0" |
| 500 yards | −43.8" | −46.5" | −40.0" |
| 600 yards | −77.0" | −81.2" | −68.0" |
Inside 300 yards, all three loads are within 1" of each other in this table. The differences increase at 400+ yards. At 600 yards the OTM drops 9" less than M193 and 13" less than M855.
How do the loads drift in a 10 mph crosswind?
10 mph full-value crosswind, 16" barrel:
| Distance | M193 (55gr) | M855 (62gr) | 77gr OTM |
|---|---|---|---|
| 200 yards | 3.4" | 3.2" | 2.4" |
| 300 yards | 8.0" | 7.6" | 5.7" |
| 400 yards | 15.0" | 14.2" | 10.6" |
| 500 yards | 24.8" | 23.4" | 17.4" |
| 600 yards | 38.2" | 35.8" | 26.4" |
At 600 yards, the 77gr OTM drifts 11.8 inches less than M193 in the stated 10 mph crosswind. The difference depends on the wind and ballistic assumptions used here.
How much energy do the loads retain at 600 yards?
| Distance | M193 (55gr) | M855 (62gr) | 77gr OTM |
|---|---|---|---|
| Muzzle | 1,135 ft-lbs | 1,213 ft-lbs | 1,293 ft-lbs |
| 200 yards | 745 ft-lbs | 820 ft-lbs | 969 ft-lbs |
| 400 yards | 469 ft-lbs | 534 ft-lbs | 718 ft-lbs |
| 600 yards | 282 ft-lbs | 330 ft-lbs | 518 ft-lbs |
At 600 yards, the 77gr OTM retains 40% of its stated muzzle energy, while M193 retains 25%. Those percentages describe this ballistic model, not a load recommendation.
What differences do the three load tables show?
- M193 (55gr): The highest muzzle velocity of the three in these tables. Retains 25% of its stated muzzle energy at 600 yards. Current tracked prices are on the linked caliber page rather than inferred from this ballistic model.
- M855 (62gr): Steel-core penetrator; velocity and energy sit between the other two. At the 25–100 yard distances typical of range use, no measured accuracy difference from M193 is documented here.
- 77gr OTM (Federal Gold Medal Match, Black Hills Mk262-pattern): The highest ballistic coefficient of the three — it retains 40% of muzzle energy at 600 yards and drifts least in wind, per the tables above.
- Expanding defensive loads: A different construction from all three ball loads above, and measured separately in AR-15 ammo compared.
For a deeper look at all 5.56 bullet types: 5.56 ammo types explained
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- 5.56 ammo types explained — M193, M855, OTM, and more
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- .300 Blackout ballistics — Supersonic and subsonic data
- .300 Blackout vs 5.56 — AR-15 caliber comparison
Related caliber pages
- 5.56 NATO ammo prices — Current pricing across all retailers
- Cheapest 5.56 NATO right now — Lowest observed prices
- 5.56 NATO price history — 30-day pricing trends
- 5.56 FMJ — Range ammo options and pricing
- .223 Remington ammo prices — Current pricing
Search 5.56 ammo → | Search .223 ammo →
Sources
- Federal Premium Ballistics Calculator — Velocity and trajectory data
- Hornady Ballistic Calculator — BC and wind drift reference
- Bryan Litz, Applied Ballistics for Long-Range Shooting — BC measurements and trajectory modeling
- DocGKR / M4Carbine.net Terminal Ballistics — Fragmentation and terminal performance data