The exact .350 Legend bullet diameter is 0.357 inches, which converts to 9.07 millimeters.While .350 Legend ammunition is available with different bullet weights, the cartridge’s nominal projectile diameter remains exactly the same across all factory loads.This measurement refers specifically to the width of the bullet itself, which differs from the internal dimensions of the barrel. Specifically, the .350 Legend utilizes a narrower bore diameter of 0.346 inches and a groove diameter of 0.355 inches to ensure a tight gas seal upon firing.
350 Legend Bullet Diameter
| Specification | .350 Legend |
| Nominal Bullet Diameter | 0.357 inches |
| Bullet Diameter In Inches | 0.357″ – 0.003″ |
| Bullet Diameter In Millimeters | 9.07 mm |
| Groove Diameter | 0.355 inches |
| Bore Diameter | 0.346 inches |
| Typical Bullet Weights | 145 gr to 255 gr |
| Case Length | 1.710 inches |
| Overall Cartridge Length | 2.260 inches |
| Maximum Pressure | 55,000 PSI |
What Is The 350 Legend Bullet Diameter?
The 350 Legend bullet diameter is the physical width of the unfired projectile seated in the cartridge case. Winchester engineered the cartridge to fire a nominally .357-caliber bullet, allowing it to meet the legal requirements of states that mandate straight-walled cartridges for deer hunting. Because state laws often require a minimum bullet diameter of .35 caliber (0.350 inches), the 0.357-inch projectile safely exceeds this legal threshold.
350 Legend Bullet Diameter In Inches
According to the official Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) specifications, the 350 Legend bullet diameter in inches is officially listed as 0.357″ with a tolerance of -0.003″. This means that factory projectiles can technically measure anywhere between 0.354 inches and 0.357 inches and still fall within safe and acceptable manufacturing tolerances. However, the accepted nominal measurement is 0.357 inches.
350 Legend Bullet Diameter In Millimeters
For those using the metric system, the 350 Legend bullet diameter in mm is 9.07 mm. Because 1 inch equals 25.4 millimeters, multiplying 0.357 by 25.4 gives you precisely 9.0678 mm, which rounds to 9.07 mm.
350 Legend Bullet vs Bore Diameter
A common point of confusion among shooters is the difference between the bullet size and the barrel’s bore diameter. The 350 Legend bore diameter is 0.346 inches. The bore diameter measures the distance across the “lands” (the raised portions of the rifling inside the barrel). The unfired 350 Legend projectile diameter is physically wider (0.357″) than the bore so that the rifling can aggressively grip the bullet, imparting the spin necessary for stable flight.
350 Legend Groove Diameter
The 350 Legend groove diameter is 0.355 inches. The groove diameter measures the distance across the deepest cuts (the grooves) inside the rifled barrel. When the 0.357-inch bullet travels down the barrel, it is swaged (squeezed) slightly to fill the 0.355-inch grooves. This tight physical fit traps the 55,000 PSI of expanding gases directly behind the bullet, maximizing velocity and accuracy.
350 Legend Bullet Weights
While the cartridge diameter is fixed, you can select different projectile masses depending on your application. The 350 Legend bullet weight typically ranges from lightweight 125-grain solid copper hunting rounds up to heavy 255-grain subsonic loads. Changing the weight alters the bullet’s length and mass, but the diameter remains exactly 0.357 inches.
Bullet Diameter vs Other Cartridges
Shooters must be careful when looking at caliber names, as the marketing name does not always reflect the exact measurement. Here is how the 350 Legend dimensions compare to other popular rounds:
| Cartridge | Bullet Diameter | Diameter In mm |
| .350 Legend | 0.357″ | 9.07 mm |
| .357 Magnum | 0.357″ | 9.07 mm |
| .357 SIG | 0.355″ | 9.02 mm |
| .35 Remington | 0.358″ | 9.09 mm |
| .355 / 9mm | 0.355″ | 9.02 mm |
| .308 Winchester | 0.308″ | 7.82 mm |
Notice that the .357 SIG actually fires a 0.355-inch bullet (the same as a 9mm), while the .350 Legend fires a 0.357-inch bullet. Never assume a bullet’s true diameter based purely on the name stamped on the box.
Bullet Weight
Ammunition manufacturers have developed several specialized loads for the 350 Legend. The most common bullet weights fall between 150 and 180 grains for hunting whitetail deer and feral hogs.
| Bullet Weight | Example Load | Bullet Type | Advertised Velocity |
| 145 grain | Winchester White Box | FMJ | 2,250 fps |
| 150 grain | Winchester Deer Season XP | Extreme Point | 2,325 fps |
| 165 grain | Hornady Custom | FTX | 2,200 fps |
| 180 grain | Winchester Super-X | Power-Point | 2,100 fps |
| 180+ grain | Winchester Super Suppressed (255 gr) | Open Tip | 1,060 fps |
Velocities are generally recorded from a 20-inch test barrel.
Dimensions
To understand how the cartridge fits into the AR-15 platform and standard bolt-action rifles, here are the complete SAAMI-verified 350 Legend dimensions:
| Dimension | Measurement |
| Bullet Diameter | 0.357″ |
| Groove Diameter | 0.355″ |
| Bore Diameter | 0.346″ |
| Case Length | 1.710″ |
| Overall Length | 2.260″ |
| Base Diameter | 0.390″ |
| Neck Diameter | 0.378″ |
| Shoulder Diameter | None (Tapered Straight-Wall) |
| Rim Diameter | 0.378″ |
| Maximum Pressure | 55,000 PSI |
350 Legend vs 357 Magnum
Because both cartridges share a 0.357-inch bullet diameter, many shooters wonder how the 350 Legend vs 357 Magnum compare.
Despite sharing a bullet diameter, they are entirely different cartridges designed for different weapon platforms:
- Platform:The .357 Magnum is a rimmed revolver cartridge, whereas the 350 Legend is a rimless rifle cartridge built specifically to function in AR-15s and modern bolt-action rifles.
- Pressure and Velocity:The 350 Legend operates at a massive 55,000 PSI, pushing a 150-grain bullet at over 2,300 fps.The .357 Magnum operates at a much lower 35,000 PSI.
- Energy:The 350 Legend delivers significantly more muzzle energy and downrange lethality, carrying an effective range of roughly 250 yards on deer, compared to the much shorter range of a .357 Magnum.
They are absolutely not interchangeable. You cannot fire a .357 Magnum in a 350 Legend chamber, nor vice versa.
350 Legend Bullet Diameter: Exact Measurement
The exact .350 Legend bullet diameter is 0.357 inches, or 9.07 millimeters.
While the actual projectile measures 0.357 inches across, it is fired through a barrel with a 0.346-inch bore diameter and a 0.355-inch groove diameter. This intentional sizing discrepancy forces the copper jacket of the bullet to squeeze tightly into the barrel’s rifling grooves. This process creates a perfect seal behind the bullet, preventing high-pressure expanding gases from escaping past the projectile while ensuring the bullet stabilizes in flight.
FAQs
What is the bullet diameter of 350 Legend?
The nominal bullet diameter is 0.357 inches.
What is 350 Legend bullet diameter in mm?
In metric measurements, the diameter is 9.07 millimeters.
Is 350 Legend actually .357 inches?
Yes, despite the “350” in its name, the cartridge utilizes a .357-inch projectile.
Is 350 Legend the same diameter as 357 Magnum?
Yes, both cartridges use a 0.357-inch diameter bullet, but they have completely different case lengths, pressures, and profiles.
What is the bore diameter of 350 Legend?
The barrel’s internal bore diameter (measured land-to-land) is 0.346 inches.
What is the groove diameter of 350 Legend?
The barrel’s internal groove diameter (measured groove-to-groove) is 0.355 inches.
What bullet weights are available for 350 Legend?
Factory loads typically range from 125 grains to 255 grains, with 150-grain, 165-grain, and 180-grain being the most common for hunting.
What is the case diameter of 350 Legend?
The case is slightly tapered. It has a base diameter of 0.390 inches and narrows down to a neck diameter of 0.378 inches to hold the bullet.
Is 350 Legend a 35 caliber?
Yes. Legally and practically, any bullet measuring 0.350 inches or larger qualifies as a .35 caliber, making the 0.357-inch Legend legal for straight-walled hunting restrictions.
How does 350 Legend bullet diameter compare with 9mm?
A standard 9mm Luger bullet measures 0.355 inches, making the 350 Legend (0.357 inches) slightly wider.
How does 350 Legend bullet diameter compare with 308?
The 350 Legend (0.357″) is significantly wider than the .308 Winchester, which utilizes a 0.308-inch projectile.
Is 350 Legend the same as 357 Magnum?
No. The 350 Legend is a high-pressure (55,000 PSI) rimless rifle cartridge with a 1.710-inch case. The 357 Magnum is a rimmed revolver cartridge. They only share the same bullet diameter.