5.56 Velocity by Barrel Length
Velocity by barrel length for 5.56x45mm NATO cartridge. Information is from multiple sources including RifleShooter.com and Sonoran Desert Institute. We'll also discuss best barrel length for something like an AR-15 pistol as well as "SPR" / DMR-type setup below, to help you to better navigate various typical barrel length offerings.
We'll also include velocity data for .223 Remington further down, for easier access without needing to leave the page. For the dedicated page, see - .223 Remington Velocity by Barrel Length
|Barrel Length||Federal XM193 (55 gr. FMJ)||Winchester M855 (62 gr. Penetrator)|
|26"||3431 fps||3280 fps|
|25"||3426 fps||3229 fps|
|24"||3409 fps||3188 fps|
|23"||3350 fps||3169 fps|
|22"||3366 fps||3158 fps|
|21"||3305 fps||3117 fps|
|20"||3306 fps||3097 fps|
|19"||3259 fps||3060 fps|
|18"||3202 fps||3052 fps|
|17"||3151 fps||2972 fps|
|16.5"||3187 fps||2992 fps|
|14"||3039 fps||2808 fps|
|13"||2974 fps||2694 fps|
|12"||2919 fps||2646 fps|
|11"||2834 fps||2579 fps|
|10"||2767 fps||2489 fps|
|9"||2662 fps||2403 fps|
|8"||2520 fps||2296 fps|
|7"||2410 fps||2135 fps|
|6"||2202 fps||1955 fps|
.223 Remington Velocity by Barrel Length
For easy access for those looking, we've included velocity data for .223 Remington on this page as well. Data for Black Hills 68 gr. and Remington UMC 55 gr. FMJ are from RifleShooter.com. The velocity data for Remington UMC 45 gr. and 50 gr. JHP's are sourced from Ballistics By The Inch. For the dedicated page, see - .223 Remington Velocity by Barrel Length
|Barrel Length||Black Hills 68 gr. Match||Remington UMC 55 gr. FMJ||Remington UMC 50 gr. JHP||Remington UMC 45 gr. JHP|
|26"||2849 fps||3182 fps||--||--|
|25"||2828 fps||3221 fps||--||--|
|24"||2804 fps||3211 fps||--||--|
|23"||2775 fps||3131 fps||--||--|
|22"||2774 fps||3111 fps||--||--|
|21"||2762 fps||3090 fps||--||--|
|20"||2740 fps||3071 fps||--||--|
|19"||2699 fps||3028 fps||--||--|
|18"||2679 fps||3006 fps||3179 fps||3354 fps|
|17"||2652 fps||2922 fps||--||--|
|16.5"||2632 fps||2968 fps||--||--|
|16"||--||--||3076 fps||3257 fps|
|14"||2524 fps||2808 fps||2901 fps||3099 fps|
|12"||2424 fps||2646 fps||2964 fps||2943 fps|
|10"||2314 fps||2489 fps||2682 fps||2776 fps|
|8"||2121 fps||2296 fps||2478 fps||2536 fps|
|6"||1865 fps||1955 fps||2153 fps||2189 fps|
|5"||--||--||1921 fps||1939 fps|
|4"||--||--||1674 fps||1709 fps|
|3"||--||--||1276 fps||1277 fps|
Best Barrel Length For 5.56 NATO
For Subsonic Loads
Many will advise against bothering with subsonic loads using heavier bullets in a 5.56 firearm and instead opt for an AR-15 chambered in .300 Blackout, since it will have better muzzle energy due to much heavier bullets at the same velocities. Still, a typical 16" barrel with 1-in-7 twist rate (for heavier bullets) and a suppressor of your choosing should work acceptably well overall and still retain a lot more energy than a .22 LR. Likewise, a handier barrel in the 10-inch range and a typical 6-7" suppressor should also be a good setup for a pistol or SBR build. As if often the case, it depends what the user is looking for. But overall, for an optimal AR-15 type rifle with suppressor, 5.56 should not be your first option unless you want it for fun or will also be shooting standard velocity ammo and so on.
For Maximum Velocity
For maximum velocity with 5.56x45mm NATO, a 20-inch barrel will give the most velocity possible out of a common barrel length rifle. For best accuracy, a heavy / bull barrel is preferred. Theoretically, a 22-inch barrel would be the best combination between somewhat manageable maneuverability and maximum velocity, but it's a non-standard length. Anything longer is even more non-standard, and has diminishing returns, though still does offer velocity advantage. But excessive barrel lengths like this should probably only ever be considered if you plan on shooting at 1,000 yards with a dedicated benchrest setup, which is also uncommon. For most applications, an 18" heavy barrel will still offer velocity advantage over a typical 16" barrel and plenty of accuracy. Consider that this is the basic setup of the U.S. military's former Mk 12 Mod 0 "SPR" (Special Purpose Rifle), which was said to have an effective range up to 700 meters.
Note: If you're looking for absolute maximum range from something like an AR-15 platform, it may be worth considering cartridges like the 6.5 Grendel, .224 Valkyrie, and others. The 6mm ARC seems to have impressive potential from our understanding. Also consider the lesser-known .277 Wolverine, which is a bridge between the .223/5.56 and .300 Blackout, and uses the same .223/5.56 cases to load with.
Best Overall Barrel Length for 5.56 NATO
Best barrel length for 5.56mm (and .223 Remington) depends on your use case. For an overall great rifle, there's nothing wrong with the most popular barrel length of 16 inches. It doesn't have any major disadvantages in velocity and is still overall quite maneuverable. For a pistol or SBR setup, if trying to maintain decent velocity and meneurverability, anything less than a barrel in the 10-inch range seems like a hard sell because velocity begins to drop heavily. When using a silencer / suppressor, also be sure to keep in mind that many manufacturers have a minimum barrel length for requirement for their warranties, which is often (but not always) about 10 inches or above in the case of common 5.56mm suppressors. Also consider that longer barrels will work better with a suppressor. As a result, most who want a suppressor may want to opt for a barrel in the 10 inch range, which works out if you want a pistol-type setup for use with and without a suppressor. Since many silencers are in the 6" to 7" range, this gives a similar length to a typical 16" barrel AR-15, and also give some velocity advantage over an unsuppressed 10 inch barrel.
- Velocity by Barrel Length of Various Calibers
- 5.56x45mm NATO
- .277 Wolverine
- .300 Blackout
- .300 HAM'R
- 6mm ARC
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