5.45 vs. 5.56: Are These Cartridges That Different?

Last Updated: Jan 14, 2026

The 5.45x39mm vs. 5.56x45mm: two historied cartridges that have battled it out on the front lines for decades. That leaves many shooting enthusiasts wondering which is better. As you continue reading, you’ll learn the differences between the two cartridges – and which one is better for your shooting needs. Let’s compare and contrast 5.45 vs. 5.56!

Overview of the 5.45x39mm and 5.56x45mm

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The 5.45x39mm was developed by the Soviet Union and adopted into service in 1974 for use in the AK-74 rifle. The Soviets’ goal had been to develop a cartridge similar to NATO allies’ 5.56x45mm (but not so similar that allies could use captured stashes of Russian ammo in combat). To this end, they were successful.

The 5.56x45 was developed by FN Herstal. The nearly identical 223 Remington had been developed by Remington and Fairchild Industries for the U.S. Continental Army Command (CONARC) in 1957. The 5.56 was officially adopted by the U.S. Armed Forces in 1963, primarily for use in the M16 rifle.

Both cartridges allow soldiers to carry more ammunition into battle (relative to larger rifle cartridges, such as the 7.62x51mm NATO and 7.62x54mm), have low recoil, and offer similar ballistic performance to one another when loaded with similar bullets.

5.45 and 5.56 Pros and Cons

5.45		5.56
Pros	Cons	Pros	Cons
Low recoil	Limited stopping power	Low recoil	Limited stopping power
Lightweight	Older USSR surplus may be corrosive	Lightweight
Flat trajectory	Older USSR surplus may be corrosive	High availability
Good effective range	Limited availability	Inexpensive

Ballistics Comparison: Velocity, Energy, and Bullet Drop

Note: The following information comes from ammunition manufacturers. Actual ballistics obtained with your firearm can vary considerably from those advertised. Also, ballistics can vary from lot to lot with the same brand and load type.

Cartridge	Bullet	Barrel Length (in)	G1 BC	Velocity (fps)						Energy (ft-lbs)						Elevation (in)
Cartridge	Bullet	Barrel Length (in)	G1 BC	0yds	100yds	200yds	300yds	400yds	500yds	0yds	100yds	200yds	300yds	400yds	500yds	0yds	100yds	200yds	300yds	400yds	500yds
5.56x45	60gr Ballistic Tip	24	0.270	3200	2838	2505	2195	1908	1647	1,364	1,074	836	642	485	361	-1.5	1.4	0.0	-7.0	-21.2	-45.1
5.45x39	60gr V-MAX	16	0.285	2810	2495	2202	1929	1678	1456	1,052	830	646	496	375	282	-1.5	2.1	0.0	-9.3	-28.0	-59.1

Recoil and Shooting Experience

Having owned several 5.56 rifles over the years, I’ve lost count of the number of times new shooters have shown surprise by how little it kicks. You can expect 5 to 6 ft-lbs of recoil energy hitting your shoulder while firing a 7-pound rifle. (That’s comparable to your buddy gently punching you.) The 5.56 is one of my favorite cartridges for shooting targets within 200 yards because it’s accurate, and its low recoil means I can spend hours at the range without earning a sore shoulder.

The 5.45x39 delivers even lighter recoil. You can expect 2.5 ft-lbs of energy pushing against your shoulder while firing an AK-74. That’s hardly noticeable. Its gentle kick allows quicker follow-up shots and better accuracy. The 5.45 is known for its high velocity and relatively flat trajectory, which both contribute to its generous effective range.

Accuracy and Effective Range

Both cartridges are highly accurate in the hands of a capable shooter. The 5.45x39 tends to have an effective range of up to 500 yards, while the 5.56 boasts an effective range out to 600.

Penetration and Terminal Ballistics

Penetration depth and terminal ballistics are highly dependent on bullet selection. Most 5.45x39mm bullets are designed to tumble upon impact, which can establish a large wound cavity. On the other hand, most 5.56x45mm bullets are designed to fragment upon impact, which can inflict more soft tissue damage. The 5.56 has a slight advantage in stopping power and wounding potential, whereas the 5.45 offers superior penetration against light barriers.

5.45 vs. 5.56 Cartridge Specs

	5.45x39	5.56x45
Parent Case	7.62x39mm	223 Remington
Bullet Diameter	0.220"	0.224"
Neck Diameter	0.248"	0.253"
Base Diameter	0.394"	0.377"
Case Length	1.568"	1.760"
Overall Length	2.244"	2.260"
Case Capacity	27.0 grains H₂O	28.5 grains H₂O
Max Pressure	51,488 psi (C.I.P.)	62,366 psi (EPVAT)

As you can see in the specs table, the 5.45x39 was derived from the 7.62x39mm, which was originally designed for the AK-47. The Soviets developed the 5.45x39 using a similar case design with a smaller bullet diameter, creating a more modern intermediate cartridge with improved ballistics.

Which Is Better for Home Defense or Tactical Shooting?

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I don't typically recommend using a rifle for home defense. The risk of over-penetration is too high compared to a pistol or shotgun. However, if I were forced to choose between only the 5.45 and 5.56, then as a true red, white, and blue-blooded American, I would choose the 5.56 as the better cartridge for home defense and tactical shooting. It is loaded with a wider selection of bullets, easier to find for sale, and significantly less expensive to train with.

Which Is Better for Hunting?

The 5.56 is better for hunting because it has many more bullet options designed for hunting. Both will work for small and some medium game. Varmint hunting is where the 5.56 shines best.

Which Is Better for Range Shooting?

If you live in the U.S., the 5.56 is the better choice for range shooting because there is much more ammo available at lower prices. While the recoil of the 5.45 is lighter, the 5.56 is hardly a shoulder bruiser. Ultimately, either round's recoil is inconsequential.

Final Verdict: 5.45 or 5.56?

For those of us in the U.S., it's a no-brainer: the 5.56 is the better option. It has slightly more recoil (even though it's technically double, it's barely noticeable), but there is also a wider selection of higher-quality and lower-priced ammo. Ballistic performance is similar (when both rounds are loaded with similar bullets), but the 5.56 tends to be more versatile than the 5.45, all the same.

Written by

Wes Littlefield

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