Ever wondered how long is a full size M4 carbine in real life? The standard rifle measures about 33 inches (83.8 cm) end to end with the stock extended. This guide covers its length, weight, and size next to common objects and other rifles.
M4 Carbine Length Quick Conversion
| Model | Length (mm) | Length (in) |
|---|---|---|
| M4 carbine, stock extended | 838 mm | 33 in |
| M4 carbine, stock retracted | 756 mm | 29.75 in |
| M4 carbine barrel | 368 mm | 14.5 in |
| AK-47 | 870 mm | 34.3 in |
| M16A2 | 1,003 mm | 39.5 in |
Quick tip: Lengths are overall lengths and vary by variant and source. To convert millimeters to inches, divide by 25.4. To convert inches to centimetres, multiply by 2.54.
Quick Reference List of M4 Carbine Sizes
| Category | Details |
|---|---|
| Full-Size Length | Overall length, barrel length |
| Variants & Folded Length | Stock retracted, M4A1 (same length) |
| Comparisons With Everyday Objects | Baseball bat, yardstick, kitchen counter, acoustic guitar |
| Comparisons With Other Rifles | AK-47, M16A2 |
| Weight & Capacity | Unloaded weight, standard 30-round magazine |
| Cartridge Size | 5.56x45mm bullet diameter, case length, overall length |
Full-Size M4 Carbine Length and Overall Dimensions
The standard M4 carbine with its adjustable stock extended is the “full-size” version most people mean.
Overall Length (Stock Extended)
The M4 carbine with the stock extended has an overall length of 33 inches (838 mm). That figure is measured from the butt of the stock to the muzzle. As a decimal, that equals 2.75 feet.
Exact numbers can shift a little by maker and production year, so treat the M4 carbine length as an approximate value. Most published sources list it at 33 inches with the stock extended.
Barrel Length
The standard M4 carbine barrel is 14.5 inches (368 mm) long. That is just under half of the rifle’s total length.
Half of the M4 carbine’s 33 inches would be 16.5 inches, so the barrel is about 2 inches shorter than that. This ratio helps explain how big an M4 carbine looks in photos.
Length in CM and MM
The M4 carbine measures 83.8 cm or 838 mm from end to end with the stock extended. As a decimal, that equals 0.838 meters.
Multiply the M4 carbine’s 33 inches by 2.54 to check the math, and you get 83.82 cm. Use this M4 carbine length in cm for any metric listing. With the stock retracted, it measures 75.6 cm or 756 mm.
M4 Carbine Variants and Their Lengths
Not every M4-pattern carbine is the same length, so here is how the stock positions compare.
M4 Carbine With Stock Retracted
The M4 carbine with its adjustable stock fully retracted measures 29.75 inches (756 mm) overall. That is 3.25 inches (about 8.3 cm) shorter than the 33-inch extended length.
Retracting the stock cuts its length by roughly a tenth of its full size. The barrel stays 14.5 inches in both positions, so the whole 3.25-inch difference comes from the stock alone. This short retracted length is the reason designers added the adjustable stock, so the same rifle can be made more compact for storage and transport.
M4A1 Length
The M4A1 is the full-automatic version of the M4 carbine, and it is the same length as the standard M4: 33 inches (838 mm) with the stock extended and 29.75 inches (756 mm) with the stock retracted, with the same 14.5-inch (368 mm) barrel. No different length is given for the M4A1, because its overall dimensions match the M4.
M4 Carbine Length Compared With Everyday Objects
Familiar objects make 33 inches easy to picture.
Louisville Slugger Adult Baseball Bat
A Louisville Slugger adult baseball bat is commonly sold in a 34-inch length. That is only 1 inch longer than the M4 carbine with the stock extended, and 4.25 inches longer than the retracted M4 at 29.75 inches.
Set a Louisville Slugger bat beside the M4 carbine’s 33 inches, and the two match almost exactly. This is one of the closest everyday size matches for the M4 carbine.
Standard Yardstick
A standard yardstick measures 36 inches, which is 3 inches longer than the M4 carbine’s 33 inches with the stock extended, and 6.25 inches longer than the retracted M4 at 29.75 inches. The yardstick is a handy tool for checking this length.
Yamaha Acoustic Guitar
A full-size Yamaha acoustic guitar measures about 40 to 41 inches from headstock to bottom. That makes the Yamaha guitar about 7 to 8 inches longer than the M4 carbine with the stock extended, and about 10.25 to 11.25 inches longer than the retracted M4.
Lay a Yamaha acoustic guitar on a table, and the M4 carbine would reach roughly to the guitar’s lower bout. This comparison helps show the size of an M4 carbine next to a musical instrument.
M4 Carbine Length Compared With Other Rifles
Side-by-side sizes show where the M4 carbine sits among well-known rifles.
M4 Carbine vs AK-47 Length
The AK-47 measures about 34.3 inches (870 mm), which is roughly 1.3 inches longer than the M4 carbine with the stock extended, and about 4.55 inches longer than the retracted M4 at 29.75 inches.
The M4 carbine’s 33 inches versus the AK-47’s 34.3 inches is a gap of about 4 percent. That small gap is why the two rifles look so alike in photos.
M4 Carbine vs M16A2 Length
The M16A2 measures about 39.5 inches (1,003 mm), which is roughly 6.5 inches longer than the M4 carbine with the stock extended, and about 9.75 inches longer than the retracted M4. The M16A2 is a US-made rifle used by American forces, and the M4 carbine was developed in the United States during the 1980s as a shortened version of the M16 rifle.
An M16A2 is about 20 percent longer than the M4 carbine’s 33 inches. Placed side by side, the M4 carbine length looks noticeably shorter.
M4 Carbine Weight and Magazine Size
Weight and capacity round out the picture of how big an M4 carbine is.
How Much Does an M4 Carbine Weigh?
An M4 carbine weighs 6.43 pounds (2.92 kg) empty. With a 30-round loaded magazine and sling, it weighs 7.75 pounds (3.52 kg). The difference of 1.32 pounds is the combined weight of the loaded magazine and the sling.
Standard 30-Round Magazine Capacity
The standard M4 carbine magazine holds 30 rounds. Larger-capacity magazines exist, but 30 is the most common size.
5.56x45mm Cartridge Size (Measurement Facts)
The cartridge is often the next size question people ask.
5.56x45mm Bullet Diameter
The 5.56x45mm cartridge’s bullet is about 5.70 mm (.224 inches) wide. The “5.56” in the name is a nominal bore figure, not the exact bullet width.
A 5.70 mm bullet is slightly narrower than a standard pencil, which is roughly 7 mm. Check the published specs for any particular cartridge, since sizes vary slightly by maker.
5.56x45mm Case and Overall Length
The 5.56x45mm cartridge case is about 44.7 mm (1.76 inches) long. The complete cartridge, bullet included, is about 57.4 mm (2.26 inches).
A US quarter is 0.955 inches wide, so the 5.56x45mm case is a little under two quarters wide. The full cartridge is a little longer than the short side of a credit card, which is about 2.1 inches.
FAQs About M4 Carbine Length
How long is a full size M4 carbine?
A full-size M4 carbine is 33 inches (83.8 cm) long with the stock extended. That is 2.75 feet end to end.
How long is an M4 carbine in cm?
An M4 carbine is 83.8 centimeters long with the stock extended, or 838 millimeters. With the stock retracted it is 75.6 centimeters. Multiply inches by 2.54 to convert.
How long is an M4 carbine barrel?
The standard M4 carbine barrel is 14.5 inches (368 mm). That is just under half the rifle’s length.
How much does an M4 carbine weigh?
An M4 carbine weighs 6.43 pounds (2.92 kg) empty, and 7.75 pounds (3.52 kg) with a 30-round loaded magazine and sling.
How long is an M4 carbine with the stock retracted?
An M4 carbine is 29.75 inches (756 mm) long with the stock retracted. That is 3.25 inches shorter than the 33-inch extended length.
Is the M4A1 the same length as the M4 carbine?
Yes. The M4A1 is the same length as the standard M4: 33 inches with the stock extended and 29.75 inches with the stock retracted, with the same 14.5-inch barrel.
Conclusion
Now you know how long a full size M4 carbine is, about 33 inches or 83.8 cm with the stock extended, and 29.75 inches or 75.6 cm with the stock retracted. Compared with a baseball bat, a yardstick, or other rifles, the size is easy to picture. Remember that length shifts slightly by model, maker, and stock type.
Related Guides
- How Long Is an HK416 Rifle? — https://measuredimension.com/how-long-is-an-hk416-rifle/
- How Long Is an FN SCAR Rifle? — https://measuredimension.com/how-long-is-an-fn-scar-rifle/
- How Long Is an AK-47? — https://measuredimension.com/length-ak-47/
- How Long Is a Glock 17? — https://measuredimension.com/how-long-is-a-glock-17/
Hi, I’m Michael Carter, I write simple, everyday size guides so you can picture any measurement in seconds.
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