Reliable 5.56 reloading data can be found in published load manuals from Western Powders, Hornady, Sierra, and the Hodgdon online data center. Published data normally includes the specific bullet manufacturer, bullet weight, powder type, starting powder charge, maximum powder charge, muzzle velocity, and the test barrel length. Available data predominantly represents military standard bullet weights like 55 grain and 62 grain, as well as heavy match projectiles like 69 grain and 77 grain. Reputable powder manufacturers such as Hodgdon, Ramshot, Accurate, and Alliant currently publish dedicated 5.56 data optimized for modern rifles. Results vary drastically by bullet design, powder burn rate, military crimped primer usage, brass case wall thickness, barrel length, and individual firearm configuration.
5.56 Reloading Data
| Bullet | Bullet Weight | Powder | Published Starting Load | Published Maximum Load | Published Velocity | Barrel Length / Firearm | Source |
|---|---|---|---|---|---|---|---|
| Hornady RRLP | 55 grain | Ramshot TAC | 25.0 gr | 27.0 gr | 2873 fps to 3161 fps | 20 inch Barrel | Hornady |
| Hornady RRLP | 55 grain | Hodgdon H335 | 22.4 gr | 24.4 gr | 2670 fps to 2949 fps | 20 inch Barrel | Hornady |
| Hornady TAC-X | 62 grain | Hodgdon Varget | 25.2 gr | 27.2 gr | 2841 fps to 3055 fps | 20 inch Barrel | Hornady |
| Hornady TAC-X | 62 grain | Ramshot TAC | 25.0 gr | 27.0 gr | 2922 fps to 3142 fps | 20 inch Barrel | Hornady |
| Berry’s FMJ | 62 grain | Hodgdon CFE 223 | Not Specified | 26.5 gr | 2752 fps | 16 inch Bushmaster AR-15 | Independent Testing |
| Sierra HPBT MatchKing | 77 grain | Ramshot TAC | 21.3 gr | 23.7 gr | 2625 fps to 2868 fps | 24 inch Barrel | Western Powders |
| Sierra Tipped MatchKing | 77 grain | Accurate 2520 | 24.7 gr | 25.3 gr | Not Specified | AR-15 Platform | Independent Testing |
Understanding The 5.56 Reloading Data
When consulting a 5.56 load data chart, it is critical to understand what the measurements mean to ensure safe 5.56 load development.
- Starting load: The minimum tested powder charge recommended to safely cycle a semi-automatic action and clear the barrel.
- Maximum published load: The absolute safe ceiling for a powder charge tested by a publisher before reaching over-pressure conditions.
- Velocity: Measured in feet per second (fps), showing how fast the projectile moves at the muzzle.
- Pressure: The internal chamber pressure. The 5.56 NATO has a higher maximum pressure rating (62,350 psi per CIP/NATO specs) than the standard .223 Remington (55,000 psi per SAAMI).
- Bullet weight: The mass of the projectile in grains.
- Powder: The specific chemical propellant.
- Barrel length: The length of the test barrel, which significantly dictates the recorded velocity.
- Firearm used for testing: Indicates whether testing occurred in a universal receiver or a standard AR-15 gas operated rifle.
- Test conditions: Atmospheric variables present during the manufacturer’s testing sequence.
- Cartridge overall length (COAL): The total length of the loaded ammunition. Hornady tests their 55 grain loads at a COAL of 2.240 inches to ensure proper magazine feeding.
Different published sources may produce different results because internal military brass volume, primer ignition heat, and the specific chamber leade of a test rifle directly alter the powder burn curve.
5.56 Bullet Weight Reloading Data
The 5.56 caliber features several military standard bullet weights that dominate published load data manuals.
- 55 grain: The original M193 military specification weight. There is massive amounts of 5.56 reloading data for this weight, utilizing fast burning powders like H335 to achieve velocities over 3,100 fps in 20 inch barrels.
- 62 grain: The modern M855 military specification weight. This weight provides enhanced penetration. Extensive data exists for 62 grain FMJ and steel core penetrator bullets, often paired with powders like Varget and CFE 223.
- 69 grain: A highly popular match weight for target shooters. It bridges the gap between standard military ammunition and heavy precision loads, typically requiring a 1:9 or 1:8 barrel twist rate to stabilize properly.
- 77 grain: The premier long range projectile, originally popularized by the Mk262 military load used in Mk12 SPR rifles. Sierra MatchKing (SMK) and Tipped MatchKing (TMK) bullets at this weight boast high ballistic coefficients for extended range accuracy.
5.56 Powder Reloading Data
| Powder | Bullet | Bullet Weight | Published Starting Load | Published Maximum Load | Published Velocity | Source |
|---|---|---|---|---|---|---|
| Ramshot TAC | Hornady RRLP | 55 grain | 25.0 gr | 27.0 gr | 2873 fps to 3161 fps | Hornady |
| Hodgdon H335 | Hornady RRLP | 55 grain | 22.4 gr | 24.4 gr | 2670 fps to 2949 fps | Hornady |
| Hodgdon Varget | Hornady TAC-X | 62 grain | 25.2 gr | 27.2 gr | 2841 fps to 3055 fps | Hornady |
| Ramshot TAC | Hornady TAC-X | 62 grain | 25.0 gr | 27.0 gr | 2922 fps to 3142 fps | Hornady |
| Hodgdon H4895 | Hornady TAC-X | 62 grain | 23.4 gr | 25.4 gr | 2807 fps to 3031 fps | Hornady |
| Ramshot TAC | Sierra HPBT | 77 grain | 21.3 gr | 23.7 gr | 2625 fps to 2868 fps | Western Powders |
5.56 Bullet And Powder Combinations
Exact component combinations are vital for reliable and safe AR-15 function.
Bullet construction influences chamber pressure. A solid copper monolithic bullet has a longer bearing surface than a lead core jacketed bullet of the identical weight, creating more barrel friction. Seating depth directly determines the cartridge overall length. Pushing a projectile deeper into the case reduces internal case capacity, which raises pressure dangerously.
Brass selection is crucial. Military 5.56 NATO cases often feature thicker internal walls than commercial .223 Remington cases, meaning powder charges must often be reduced by up to a full grain to compensate for the smaller internal case capacity. Furthermore, military primers are crimped in place and require swaging before seating a new primer. The gas port size and barrel length dictate whether a fast or slow burning powder will reliably cycle the rifle without causing violent extraction issues.
5.56 Velocity From Published Data
Comparing published 5.56 velocity data demonstrates the ballistic capabilities of different barrel lengths and loads.
- Hornady 55gr RRLP: Manufacturer data shows a maximum velocity of 3,161 fps out of a 20 inch barrel using 27.0 grains of Ramshot TAC.
- Hornady 62gr TAC-X: Manufacturer data shows a maximum velocity of 3,055 fps out of a 20 inch barrel using 27.2 grains of Varget.
- Sierra 77gr TMK: Independent chronograph testing records a velocity of 2,687 fps out of an 18 inch barrel utilizing factory equivalent loads.
It is necessary to clearly distinguish manufacturer published velocity generated in controlled environments from independent chronograph testing. Ballistic calculator estimates should never replace actual measured velocity.
5.56 Reloading Data By Barrel Length
Barrel length heavily affects published 5.56 velocity. The cartridge was originally optimized for a 20 inch barrel, which ensures complete powder combustion and maximizes velocity.
When fired from a 16 inch carbine barrel, actual muzzle velocities drop by approximately 100 fps to 150 fps compared to published 20 inch barrel data. Firing from a 14.5 inch or 10.5 inch barrel results in severe velocity loss and unburnt powder exiting the muzzle. Shooters must verify the test barrel length for every velocity figure provided in a manual to set realistic expectations.
5.56 Subsonic vs Supersonic Data
The 5.56 NATO is inherently a high velocity, supersonic cartridge. The vast majority of 5.56 reloading data focuses strictly on supersonic performance.
Supersonic 5.56 load data pushes lightweight bullets well past the speed of sound, creating massive hydrostatic shock and rapid fragmentation upon impact. While 5.56 subsonic load data exists, it is highly problematic. A 55 grain bullet traveling below 1,125 fps carries very little kinetic energy and will almost never generate enough gas pressure to cycle a standard AR-15 action. The .300 Blackout cartridge was explicitly developed to solve the subsonic limitations of the 5.56 platform.
5.56 Energy And Ballistics
Reliable source data shows that the 5.56 excels at delivering high velocity energy at intermediate ranges.
A standard 55 grain M193 equivalent load leaving the muzzle at 3,240 fps produces approximately 1,282 foot-pounds of muzzle energy. However, lightweight bullets shed velocity quickly. By 300 yards, the velocity drops to roughly 2,128 fps, carrying just 553 foot-pounds of energy.
Alternatively, a heavier 77 grain projectile with a higher ballistic coefficient retains its velocity much better. Fired at 2,687 fps, the 77 grain bullet stays supersonic out past 700 yards and delivers superior downrange energy for precision target shooting and hunting.
Manufacturer Data vs Independent Testing
Manufacturer published reloading data is derived using universal pressure barrels and precise piezoelectric pressure sensors. This data is the safest benchmark for 5.56 load development.
Independent chronograph testing occurs when reloaders test handloads in the field. While highly useful for determining actual velocities from standard AR-15 rifles, these measurements often differ from published figures due to variations in barrel wear, chamber specifications, and atmospheric conditions. Reloaders should always give absolute priority to official manufacturer data.
5.56 Pressure And Safety
Following published 5.56 reloading data exactly is paramount for safety. The 5.56 NATO chamber features a longer leade (throat) than a standard .223 Remington chamber. Firing 5.56 NATO loaded ammunition in a tight .223 Remington chamber can cause a dangerous pressure spike.
Always begin with the published starting load and work up slowly. Never jump straight to the maximum load. Swapping a standard small rifle primer for a magnum primer alters the ignition curve and raises pressure. Altering the bullet seating depth to make a shorter cartridge overall length drastically increases internal pressure. Hot summer temperatures can also cause a safe maximum load to become an over-pressure hazard.
Best Sources For 5.56 Reloading Data
The strongest current sources for 5.56 reloading data are the major powder manufacturers.
The Western Powders load guide (covering Ramshot and Accurate powders) provides a dedicated 5.56x45mm NATO section featuring pressure-tested loads that safely exceed standard .223 Remington limits. Hornady publishes highly detailed 5.56 NATO specific data in their official reloading manual, sorted cleanly by barrel lengths. Hodgdon provides an extensive, free online data center covering their entire family of powders including CFE 223, H335, and Varget.
FAQs
Where can I find 5.56 reloading data?
Authoritative 5.56 load data is published by major manufacturers like Hodgdon, Hornady, Western Powders, Sierra, and Speer.
What powders have published 5.56 data?
Published 5.56 powder profiles include Ramshot TAC, Hodgdon H335, Hodgdon CFE 223, Hodgdon Varget, Accurate 2520, and Accurate 2200 among many others.
What bullet weights have 5.56 reloading data?
Published data currently supports a wide range of bullet weights, typically spanning from 35 grain varmint bullets up to 77 grain heavy match bullets.
Does Hodgdon publish 5.56 data?
Yes, Hodgdon 5.56 load data Hodgdon tables are extensively available on their online data center for powders like CFE 223 and Varget.
Does Hornady publish 5.56 data?
Yes, Hornady 5.56 load data Hornady manuals feature dedicated NATO specification sections that test popular bullets out of standard AR-15 barrel lengths.
Is 5.56 reloading data the same as .223 Remington?
No. 5.56 NATO data is loaded to higher maximum average pressures (62,350 psi) than .223 Remington (55,000 psi) and requires a 5.56 NATO or .223 Wylde chambered rifle.
What is the difference between starting and maximum 5.56 data?
The starting load is the lowest safe powder charge recommended to cycle the weapon, while the maximum load is the highest tested powder charge that remains within safe pressure limits.
Does barrel length affect 5.56 velocity?
Yes. A 20 inch barrel will yield significantly higher velocities and allow for more complete powder combustion than a shorter 16 inch or 10.5 inch barrel.
Why does 5.56 data vary between sources?
Data varies because publishers use different test platforms, barrel lengths, brass case internal volumes, bullet bearing surfaces, and primer types.
Where can I find pressure-tested 5.56 data?
Pressure-tested data is found directly through official reloading manuals published by Western Powders, Hornady, and Hodgdon.