277 Fury vs. 308 Win: Should the Army Go Back to the 308?

By Chris Dwulet

Last Updated: Mar 23, 2026

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Chris Dwulet

Chris Dwulet grew up in the heart of the Midwest (Indiana, to be precise, a storied land which gave the world both the machine gun and the mechanical corn picker, thus solving two of mankind’s greatest age-old problems). He received his first experience with firearms in his grandfather’s backyard, where he learned to handle a Remington Model 541 with astounding deftness.

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Chris Dwulet, "277 Fury vs. 308 Win: Should the Army Go Back to the 308?"
(https://ammo.com/comparison/277-fury-vs-308)

First Shots: 277 Fury vs 308

When the U.S. Army announced that the 277 SIG Fury was the winner of the Next Generation Squad Weapon (NGSW) program contract in 2022, many American shooters were taken by surprise (myself included).

I’ve got a lot of questions that I’d like to propose to top Army brass about this decision, but none are more prescient than this:

Why not just go back to 308 Winchester?

It makes a lot of sense. The 308 Win has served the U.S. military for decades, having given soldiers long-range stopping power from rifles and belt-fed machine guns alike.

Let’s compare the 308 Winchester to the 277 SIG Fury to see which is better for your shooting needs – and surmise whether the military made a mistake by switching to a new cartridge.

What’s the Difference Between 277 Fury and 308 Win?

The main difference between the 277 Fury and 308 Winchester are their calibers. The 277 Fury fires a 0.278" diameter bullet; the 308 Win, 0.308". Despite this disparity, the rounds share the same case length.

Cartridge Specs

When comparing two centerfire cartridges, it’s good to begin by scrutinizing their physical specifications.

These rounds fire different bullets, with the 308 Winchester having a 0.308” diameter bullet and the 277 Fury having a 0.278” diameter one. The 277 Fury typically fires bullets weighing between 125 grains and 150 grains, with 135 grains being most popular. The 308 Win can fire bullets ranging from 110 grains to 220 grains.

Perhaps the biggest difference between these two cartridges are the designs of their cases.

The 308 Win has a traditional solid brass case. The 277 Fury case features a three-piece hybrid design. Instead of being entirely solid brass, the 277 Fury case consists of a stainless steel head (base), aluminum locking washer, and a brass body.

According to SIG Sauer, a stainless steel case head is required to handle the higher pressures their new cartridge produces. They aren’t kidding. The 277 Fury generates a maximum chamber pressure of80,000 psi, which is the highest ever certified by SAAMI. In comparison, SAAMI only rates the 308 Win up to 62,000 psi.

Other than their differences in bullet diameter and maximum chamber pressure, the 277 Fury and 308 Win are quite similar. Their case length is identical. Their base diameters are nearly the same. The 308's case has only 2 grains H2O more capacity than the 277 Fury's. Although the 277 Fury cartridge is said to have a unique design, these similarities have led many to theorize that the 308 Winchester is its parent case.

All in all, the 277 Fury and 308 Win are extremely similar in terms of physical specs. Let’s see how that translates in terms of recoil and external ballistics.

Recoil

Shop 277 SIG Fury Ammo

Recoil is an important consideration when purchasing a new rifle. A round with heavy recoil will be more difficult to control, and slow your rate of accurate follow-up shots.

Recoil is determined by four factors: muzzle velocity (measured in feet per second, or fps), firearm weight, bullet weight, and propellant charge weight.

In general, the 277 Fury has slightly less felt recoil than the 308 Winchester. A 277 Fury 135 grainbullet fired from an 8.6 lb SIG Sauer MCX-Spear generates around 16.8 ft-lbs recoil energy. On the other hand, a 308 Winchester 147 grain bullet has recoil of 17.1 ft-lbs. If you increase the 308 bullet's weight to 175 grains, its recoil increases to 19.4 ft-lbs.

Wen comparing similar bullet weights, the 277 Fury has slightly less recoil than the 308 Win. That said, the average shooter is unlikely to perceive any difference between the two rounds' recoil.

Trajectory, Muzzle Velocity, and Kinetic Energy

Before you commit to a caliber conversion, it’s good to compare the ballistics of either rifle cartridge and understand their capabilities.

For this example, we will compare the muzzle velocity (fps), muzzle energy (ft-lbs), and trajectory (bullet drop) for four different factory loads.

For the 277 SIG Fury, we will consider SIG's own Elite Match Grade 135 grain FMJ and Elite Bonded 150 grain polymer tip loads. For the 308 Winchester, we will compare the Nosler 150 grain Expansion Tip and Hornady Match 178 grain BTHP.

Looking at the ballistics table above, you can see that the 277 Fury surpasses the 308 Winchester in virtually every instance. When comparing the two 150 grain loads, the 277 Fury has around 15% higher muzzle velocity and nearly 30% more muzzle energy. That’s impressive considering both cartridges are virtually the same size.

The 277 Fury has a much flatter trajectory than the 308 Winchester by a wide margin. At 500 yards, the SIG round has exhibited a little over -40” of bullet drop; not much compared to the 308 Win's 56-60” bullet drop.

SIG Sauer advertises the 277 Fury as a long-range cartridge, and you can see why. According to SIG, the 2777 Fury has around 6' less bullet drop than a 6.5 Creedmoor (sometimes misspelled “Creedmore”) at 1,000 yards.

The 277 Fury 150gr polymer tip round is the only one featuring a high-pressure hybrid case SIG sells to civilians (at the time of writing, at least). That accounts for why it outperforms even the 135 grain option; the hybrid case can handle higher pressure than a traditional brass one, providing higher muzzle velocity and energy as a result.

From a ballistics standpoint, the 277 Fury cartridge outperforms the 308 Winchester at all ranges. The 277 Fury is a high-velocity, flat-shooting round that can easily reach 1,000 yards in the right hands.

Ballistic Coefficient and Sectional Density

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Ballistic coefficient (BC) is a measure of how aerodynamic a bullet is and how well it resists wind deflection. Sectional density (SD) reflects a bullet's capacity for penetration, and is determined solely by its diameter and weight. Longer and heavier bullets typically have higher BCs, as they can resist wind drift more efficiently.

For this comparison we will examine the 150 grain AccuBond: a popular hunting bullet that is available in either cartridge.

When comparing both bullets side by side, the 277 Fury has a slight edge. Its BC is 0.500 – significantly higher than the 308 Win's 0.435. (The 308 Win can easily surpass the 277 Fury's BC if its bullet is heaver.)

The 130 grain 277 Fury bullet also has the superior SD: 0.277, as opposed to 0.226 forthe 308 Win. Several other factors determine exactly how deeply a bullet will actually penetrate. But all other things being equal, the 277 Fury bullet is innately better at penetrating than any wider .30 cal bullet of the same weight.

The long, slender 0.278” diameter bullet is more aerodynamic and penetrates deeper. The 0.308” bullet can keep pace with the 277 Fury, but must be heavier in order to achieve the same BC and SD.

Accuracy

Accuracy is extremely difficult to quantify when comparing two different rifle cartridges. It is more a product of shooter and their firearm than it is of the ammo itself.

Both rounds can be extremely accurate in well-trained hands. Both are capable of accurately reaching 1,000 yards. However, given the higher muzzle velocity and flatter trajectory of the 277 Fury, th=e round will lend itself to being more accurate over greater distances.

Hunting

Shop 277 SIG Fury Ammo

When it comes to big game hunting, the 308 Winchester remains the king of the woods. The 308 Win's track record is unbeatable, and is in no danger of being supplanted by the 277 Fury.

The 308 Winchester has been THE go-to cartridge for hunting whitetail deer, feral hogs, elk, and black bear since the 1950s.

Walk into any sporting goods store across America, and I can guarantee you’ll have a huge selection of 308 hunting ammo. While the 277 Fury might offer better long-range ballistics, finding hunting ammo is extremely difficult (more on that later).

Self-Defense/Home Defense

Neither of these rounds is ideal for self-defense given how powerful they are. Both are likely to penetrate a home invader (unless they are wearing body armor) and blast into your neighbor’s home or apartment.

If I had to pick one, it would be the 308 Winchester. It is “less” likely to over-penetrate, and self-defense rounds are available such as Winchester Defender 120 grain PHP.

The 277 Fury will have no difficulty defending your life, but the 308 is still the better choice for personal protection (for the time being).

Ammo and Rifle Cost/Availability

When it comes to ammo and rifle availability, the 308 Winchester is clearly the better option.

As the 308 Win has been the preferred big game hunting cartridge (alongside the 300 Win Mag) for decades, there are an insane number of rifles and ammo varieties available.

Shop 308 Winchester Ammo

Virtually every ammo manufacturer has at least one offering in 308 Winchester, which helps keep supply high and costs low.

For inexpensive 308 plinking ammo, you should expect to pay around $1/round (at the time of writing). Cheap soft point hunting ammo can be had for a few dimes more, while premium hunting or match-grade ammo typically runs around $1.60/round.

Rifles chambered in 308 Win with a wide variety of barrel lengths and configurations are easy to find. At the time of writing, you can easily pick up a budget bolt-action hunting rifle for around $500. If you want a semi-auto rifle, you can expect to pay around $1,000 for an AR-10 or a used M1A.

If you plan to shoot 277 Fury, you’re going to need a deep ammo budget (or have Uncle Sam foot the bill.

At the time of writing, the only firearm chambered in 277 Fury available to American shooters is the SIG Cross bolt-action rifle with a 16" barrel. While it would make a lovely tricked out hunting rifle, it would will set you back at least $2,000 (and that’s if you can find one). SIG says they plan to release a new version of their semi-auto MCX-SPEAR chambered in 277 Fury, but as of December 2023, this has not happened.

277 Fury ammo is extremely difficult to find, as SIG is currentlythe only company currently manufacturing it. It is pretty pricey, too, with plain-Jane FMJ rounds costing over $2/round, and hunting ammo selling for $4/round and up.

If SIG's 277 Fury cartridge starts to become more popular, it’s likely that other ammo manufacturers will drive its cost down as they begin producing it. Until that happens, the 308 Win will remain the budget-friendlier cartridge.

Reloading

When it comes to reloading, the 308 Winchester has considerably more bullet, powder, and equipment options compared to the 277 Fury.

As an avid handloader who has lived through numerous powder, primer, and bullet shortages, I understand the benefits of having variety at the reloading bench.

Shop 277 SIG Fury Ammo

That being said, the .30 caliber bullet is one of America’s favorites. You can easily find tons of different styles and profiles to meet all your reloading needs.

There are plenty of bullets available for the 277 Fury (thanks to the popularity of the 270 Winchester) But in general, 0.278” bullets are relatively trickier to find. The biggest issue for 277 Fury handloaders at this time is a lack of reloading equipment, brass, and load data.

Only Lee Precision and Forster currently have offer loading dies for the 277 Fury. Conversely, basically, any company that manufactures reloading dies has a 308 Win option (Redding is my preference). The same thing goes for reloading data. While there are very few resources available for the 277 Fury, every reloading manual published today has load data for the 308 Win.

Good luck finding factory-new or once-fired 277 Fury brass out in the wild. Whereas 308 brass cases are extremely easy to find, 277 Fury shells are about as common as lemon drop Martinis are in Saudi Arabia.

Although I suspect these issues will iron themselves out in time, as of Q4 2023, the 308 Winchester is the better choice if you plan to reload your own hunting, plinking, or target rounds.

277 Fury vs 308 Ballistics

Below you’ll find our ballistics tables for multiple 308 Winchester and 277 Fury factory loads. These data are for reference only, as actual ballistic performance varies depending on barrel length, load, and other shooting conditions.

277 Fury Ballistics

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

For a complete breakdown of velocity, energy, and bullet drop across all available 277 Fury loads, see our 277 Fury ballistics guide.

308 Ballistics

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

For a complete breakdown of velocity, energy, and bullet drop across popular .308 loads, see our 308 ballistics guide.

277 Fury Development/History

The stopping power of the 5.56 NATO has been a heated talking point in the American shooting community – especially since the Battle of Mogadishu. Numerous small arms manufacturers have tried to replace the 5.56, but none have been successful until SIG Sauer did it in 2022.

Rounds like the 6.8 SPC, 6.5 Grendel, and 300 Blackout all fell short, but these rounds were designed to fit in the AR-15/M4 Carbine.

The 277 Fury took a different approach. Whilst designing a cartridge for the Next Generation Squad Weapon (NGSW) program, SIG Sauer looked to replace the M4 carbine, M249 SAW light machine gun (LMG), and M240 machine gun with their new M7 rifle and XM250 LMG.

The 277 Fury round can fire with or without a suppressor, and is designed to penetrate modern body armor out to 500 meters. Although military trials are still ongoing circa December 2023, the 277 Fury offers American soldiers enhanced long-range capabilities, stopping power, and armor penetration, making a strong case for it replacing 5.56 NATO.

308 Development/History

After the Korean War, the U.S. Army started developing a new round to replace the aging 30-06 Springfield and the M1 Garand.

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What they came up with is the 308 Winchester, which fits into a short action and has similar ballistics to the 30-06. The new 308 Win came chambered in the Army’s new battle rifle, the M14, but was replaced by the new M16 and 223 Remington intermediate cartridge a few years later.

Although the 308 Winchester has not been the main battle rifle cartridge for the U.S. military for decades, it has continued service in multiple machine guns as well as precision bolt-action sniper rifles.

The main success of the 308 Win came with civilian shooters and hunters, who loved the flexibility of the new cartridge and were quick to exchange their heavy long-action 30-06 rifles for lighter, more maneuverable short-action rifles.

Since then, the 308 Winchester has been one of the go-to big game hunting cartridges for many shooters. It’s unlikely that the American shooting community will give up its beloved .30 cal anytime soon. Hunters love the long-range capability offered by their 308 rifles. Ammo is inexpensive, and has considerably less recoil than heavier cartridges like the 300 Win Mag and 338 Lapua.

Check out the full history of the 308 on our 308 history page.

Parting Shots: 308 Win vs 277 Fury

Did the Army make a mistake in selecting the new 277 SIG Fury over the classic 308 Win? Probably not.

The 277 Fury utilizes new technologies to achieve ballistic and terminal performance which the 308 couldn't dream of. It’s an innovative design which gives American soldiers a longer effective range with increased stopping power, and allows them carry one type of ammo for both their battle rifles and machine guns.

For most civilian shooters, going with the 308 Winchester is the logical choice, thanks to extremely high ammo availability and a lower overall cost. (To get even better deals, visit our 308 bulk ammo page and save on your next purchase.)

If the military fully embraces the 277 Fury, then we could see more manufacturers step in to provide the shooting community with more ammo options. Until then, it just won't be nearly as practical as the tried-and-true three-oh-eight.

Written by

Chris Dwulet