The 5.56×45 is the king of American rifle cartridges. Anyone who has gone through the Army’s basic training has familiarized themself with its performance. The dominating popularity of the AR-15 on the commercial market has made the 5.56 downright ubiquitous.

But what about the 6.5 Creedmoor? It too has become very popular in recent years. That’s is quite the feat for a round that was only introduced just before the Obama era. Although optimized for long-distance shooting rather than conventional combat, would you want your first rifle chambered for 6.5 and not America’s favorite rifle round?

While they are both compatible with the AR platform, the 5.56 and 6.5 perform very differently from one another. We’re going to compare the two rounds’ dimensions, in-flight ballistics, energy, recoil and availability. Our hope is that after reading, you’ll quickly be able to decide which one you should prefer.

6.5 Creedmoor vs 5.56

Cartridge Dimensions

6.5 Creedmoor next to 5.56x45 ammunition

 5.56x456.5 Creedmoor
Parent case223 Rem30 TC
Case typeRimless, bottleneckRimless, bottleneck
Bullet diameter0.224 in0.2644 in
Neck diameter0.253 in0.295 in
Shoulder diameter0.354 in0.462 in
Base diameter0.377 in0.4703 in
Rim diameter0.378 in0.473 in
Case length1.760 in1.920 in
Overall length2.260 in2.825 in
Case capacity28.5 gr H2O52.5 gr H2O
Maximum pressure62,366 psi62,000 psi

A casual comparison of these two rounds’ dimensions reveals two important takeaways. First, the 6.5 bullet is 18 percent wider in diameter. This impacts its ballistic performance, largely because the 6.5 bullet is significantly heavier. 6.5 CDMR is typically 140 grains as opposed to the 5.56’s usual 55 grains.

Second, the 6.5’s wider and longer case creates space for a lot more propellant – the stuff that goes “BANG!” It doesn’t make use of more propellant to deliver a substantially higher muzzle velocity, but rather to push its heavier bullet out of the muzzle at a velocity nearly equal to the 5.56. Right away we see that the 6.5 has a heavier bullet than the 5.56, yet a similar muzzle velocity.

Ballistic Comparison: 6.5 CDMR vs. 5.56

In comparing the ballistics of these two rounds, it’s important to keep their intended purposes in mind. The 5.56 is meant for combat; 6.5 Creedmoor ammo is meant for long-distance shooting. To declare one round superior is to ignore the fact that they’re simply designed for different things.

Muzzle Velocity

The 6.5 CDMR certainly excels at covering greater distances. Its muzzle velocity is a little slower – except when compared to a match 5.56 round with a heavyweight 77 grain bullet, which offers a muzzle velocity in the ballpark of 2,750 fps – yet the 6.5 compensates for this with a significantly heavier and more ballistically efficient bullet.

5.56x45 Hornady Superformance 55gr GMX6.5 Creedmoor Hornady Superformance 120gr GMX
Muzzle velocity (fps)31303050
Velocity @ 100 yds27452841
Velocity @ 200 yds23922642
Velocity @ 300 yds20662451
Velocity @ 400 yds17682268
Velocity @ 500 yds15032093
Velocity @ 600 yds12811927
Velocity @ 700 yds11171768
Velocity @ 800 yds10101620
Velocity @ 900 yds9361483
Velocity @ 1000 yds8781359
5.56x45 Federal American Eagle 55gr FMJBT6.5 Creedmoor Federal American Eagle 120gr TMJ
Muzzle velocity (fps)31652900
Velocity @ 100 yds27792676
Velocity @ 200 yds24252463
Velocity @ 300 yds20972260
Velocity @ 400 yds17972066
Velocity @ 500 yds15291883
Velocity @ 600 yds13031710
Velocity @ 700 yds11321551
Velocity @ 800 yds10211406
Velocity @ 900 yds9441279
Velocity @ 1000 yds8841172
5.56x45 Sellier & Bellot 55gr FMJBT6.5 Creedmoor Sellier & Bellot 140gr FMJBT
Muzzle velocity (fps)33012658
Velocity @ 100 yds29092478
Velocity @ 200 yds25502306
Velocity @ 300 yds22182140
Velocity @ 400 yds19121981
Velocity @ 500 yds16351830
Velocity @ 600 yds13941687
Velocity @ 700 yds12001553
Velocity @ 800 yds10661430
Velocity @ 900 yds9771318
Velocity @ 1000 yds9121221

Muzzle Energy

The concept of stopping power revolves around several factors. They include things like sectional density and terminal ballistics, yet precisely how hard a bullet actually hits its target is obviously very important. The amount of energy a bullet is capable of transferring to its target boils down to exactly two variables: weight and velocity.

The 6.5 is incontestably the more powerful round. There are points in the two rounds’ trajectories when the 5.56 bullet does travel faster than the 6.5. The 6.5 bullet usually has more than twice as much mass as the 5.56, however, so its energy is superior at any given range!

For ethical deer hunting a minimum impact energy of 1,000 ft lbs is recommended. The 6.5 consistently delivers that much power at distances beyond 500 yards. Meanwhile, the 5.56 often drops to a three-digit foot-pound force by the 100 yard mark. The 6.5 typically delivers more energy at 1,000 yards than the 5.56 at 400 yards!

The two rounds’ energy difference becomes less important for self-defense. As a general rule you want at least 220 ft lbs of energy for self-defense. 5.56 is capable of putting that much energy at 500 yards, and very few self-defense scenarios play out at such ranges. (You’re not going to snipe the escaped convict creeping down the hallway to your daughter’s bedroom.)

 5.56x45 Hornady Superformance 55gr GMX6.5 Creedmoor Hornady Superformance 120gr GMX
Muzzle energy (ft lbs)11972479
Energy @ 100 yds9212151
Energy @ 200 yds6991860
Energy @ 300 yds5211601
Energy @ 400 yds3821371
Energy @ 500 yds2761168
Energy @ 600 yds200989
Energy @ 700 yds152833
Energy @ 800 yds125700
Energy @ 900 yds107586
Energy @ 1000 yds94492
5.56x45 Federal American Eagle 55gr FMJBT6.5 Creedmoor Federal American Eagle 120gr TMJ
Muzzle energy (ft lbs)12242241
Energy @ 100 yds9431908
Energy @ 200 yds7181617
Energy @ 300 yds5371361
Energy @ 400 yds3941138
Energy @ 500 yds286945
Energy @ 600 yds207780
Energy @ 700 yds157641
Energy @ 800 yds127527
Energy @ 900 yds109436
Energy @ 1000 yds96366
5.56x45 Sellier & Bellot 55gr FMJBT6.5 Creedmoor Sellier & Bellot 140gr FMJBT
Muzzle energy (ft lbs)13312197
Energy @ 100 yds10331910
Energy @ 200 yds7941653
Energy @ 300 yds6011424
Energy @ 400 yds4461221
Energy @ 500 yds3261041
Energy @ 600 yds237885
Energy @ 700 yds176750
Energy @ 800 yds139636
Energy @ 900 yds117541
Energy @ 1000 yds102464

Trajectory of 6.5 Creedmoor vs 5.56

A 6.5 creedmoor rifle pointed downrange at a shooting range

Because the 6.5’s ballistic coefficient (a measure of ability to overcome air resistance in flight, where a higher number is better) can be higher than double that of the 5.56, it retains significantly greater velocity downrange. This gives gravity less time to push the bullet downward, resulting in less of the bullet drop that complicates aiming over long distances. Its higher ballistic coefficient furthermore grants the 6.5 greater resistance to wind drift.

 5.56x45 Hornady Superformance 55gr GMX6.5 Creedmoor Hornady Superformance 120gr GMX
G1 ballistic coefficient0.2490.459
G7 ballistic coefficient0.1260.23
Elevation @ 100 yds11.758.95
Elevation @ 200 yds20.3315.06
Elevation @ 300 yds22.7916.18
Elevation @ 400 yds17.0311.5
Elevation @ 500 yds0.030.05
Elevation @ 600 yds-32.49-19.36
Elevation @ 700 yds-86.27-48.16
Elevation @ 800 yds-167.87-88.12
Elevation @ 900 yds-283.69-141.35
Elevation @ 1000 yds-438.99-210.42
5.56x45 Federal American Eagle 55gr FMJBT6.5 Creedmoor Federal American Eagle 120gr TMJ
G1 ballistic coefficient0.250.413
G7 ballistic coefficient0.1260.207
Elevation @ 100 yds11.3910.53
Elevation @ 200 yds19.7317.66
Elevation @ 300 yds22.119.05
Elevation @ 400 yds16.513.61
Elevation @ 500 yds0.020
Elevation @ 600 yds-31.45-23.45
Elevation @ 700 yds-83.48-58.83
Elevation @ 800 yds-162.58-108.71
Elevation @ 900 yds-275.2-176.21
Elevation @ 1000 yds-426.63-265.01
5.56x45 Sellier & Bellot 55gr FMJBT6.5 Creedmoor Sellier & Bellot 140gr FMJBT
G1 ballistic coefficient0.2540.49
G7 ballistic coefficient0.1270.247
Elevation @ 100 yds10.1412.12
Elevation @ 200 yds17.6220.04
Elevation @ 300 yds19.7221.41
Elevation @ 400 yds14.6815.16
Elevation @ 500 yds0.050.04
Elevation @ 600 yds-27.71-25.48
Elevation @ 700 yds-73.49-63.26
Elevation @ 800 yds-143.43-115.47
Elevation @ 900 yds-244.1-184.72
Elevation @ 1000 yds-380.96-273.98

The 5.56 is not without its merits. At shorter distances its high muzzle velocity conveys an extremely flat trajectory, making it very practical for shooting targets within a couple hundred yards. But if you judge accuracy as the ability to hit very distant targets with high reliability, then the 6.5 dominates by comparison.

6.5 CDMR vs. 5.56×45 Recoil

Heavier recoil doesn’t just make a round less comfortable to fire. It also flips your rifle’s muzzle farther upward, increasing the amount of time it takes to line up your next shot. When you want to drop a whitetail in only one shot, heavy recoil matters less. But when you want to fire multiple shots to neutralize a threat as quickly as possible, lower recoil becomes extremely useful.

While the amount of recoil you will actually feel is subjective, recoil energy is a good approximation of how hard a round will kick. To calculate it you need only factor in bullet weight, propellant weight, muzzle velocity and rifle weight. In comparing the same six rounds’ recoil energy, we’re assuming 40 grains for 6.5 Creedmoor vs 5.56 and 24 grains of propellant. We’re also firing a 12.6 pound Savage Arms 110 Elite Precision rifle, which is available chambered for either round.

 Recoil Energy (ft lbs)
5.56x45 Hornady Superformance 55gr GMX2.15
5.56x45 Federal American Eagle 55gr FMJBT2.18
5.56x45 Sellier & Bellot 55gr FMJBT2.29
6.5 Creedmoor Hornady Superformance 120gr GMX8.06
6.5 Creedmoor Federal American Eagle 120gr TMJ7.56
6.5 Creedmoor Sellier & Bellot 140gr FMJBT8.24

The results are clear: The 6.5 Creedmoor generates around three to four times the amount of recoil energy as the 5.56. We must emphasize that the 6.5’s recoil isn’t so great that it becomes uncomfortable to fire repeatedly. However, if you want a round that facilitates accurate, rapid fire, then its lighter recoil makes the 5.56 the clear winner in this contest.=

Availability & Price

The 5.56 beats the 6.5 in terms of availability. Alongside the 223 Rem, which rifles chambered for 5.56 are also capable of firing, the 5.56 ammo is the most popular cartridge in the country. If we only offered 5.56/223 and 9mm ammo for sale on this website, our guys would still keep busy.

The 6.5 Creedmoor is by no means some oddity that you’ll have to search far and wide for. Just don’t expect as great a range of options as you would while shopping for America’s number one rifle ammo. And with 5.56, you also have the option of buying military surplus.

The 5.56 beats out the 6.5 in terms of price as well. It’s a smaller, lighter round, so manufacturers can invest less lead and copper into its production. The price difference isn’t overwhelming for most hunters. If you are a bulk quantity shooter then you’re bound to prefer ammo that is about 20 percent cheaper on average though.

The Takeaway

The 6.5 Creedmoor vs 5.56 debate is settled as soon as the shooter decides what he wants.

Do you want a versatile rifle for self-defense, varmint hunting, and budget-friendly fun at the range? Then you, like countless other Americans, want the 5.56.

Are you more interested in long-distance shooting, as well as a rifle you can take deer hunting? Then you’ll quickly find out why the 6.5 has become popular.