300 Blackout vs 350 Legend is a choice between a subsonic-first .30 caliber and a straight-wall deer cartridge. Both run in an AR15 with a cartridge-specific barrel. The 350 Legend fires a wider .357-inch bullet, was designed for states that allow straight-wall cartridges for deer, and also runs subsonic with heavy bullets. The 300 Blackout fires .308-inch bullets and is designed to run heavy bullets subsonic through a suppressor from a short barrel. Chattahoochee Munitions manufactures both: the CM15 and CM7S in 300 Blackout, and the CM15 350 Legend AR15 with an 18-inch barrel.
300 Blackout vs 350 Legend at a Glance
| 300 Blackout | 350 Legend | |
|---|---|---|
| Bullet diameter | .308 inch | .357 inch |
| Case | Bottleneck, shortened .223 Remington | Straight wall, its own design |
| Case length | 1.368 inch | 1.71 inch |
| Maximum cartridge length | 2.260 inch | 2.26 inch |
| Rim | .378 inch | .378 inch |
| Subsonic loads | Designed for them, 190 to 245 gr | Fewer factory choices, such as a 250 gr load |
| Typical supersonic bullet | 110 to 150 gr | 145 to 180 gr |
| Straight-wall deer states | No (bottleneck) | Yes, where the rules allow it |
| Chattahoochee Munitions twist | 1:5 (1:7 on the 16-inch CM15) | 1:16 on the CM15 |
The 300 Blackout follows the ANSI/SAAMI centerfire rifle standard. 350 Legend dimensions are from Winchester’s published cartridge data.
300 Blackout vs 350 Legend Subsonic
Both cartridges run subsonic, and that is where most 300 Blackout owners start. For a fair 300 Blackout vs 350 Legend comparison, the table uses two loads from the same maker, with the same bullet design and the same 16-inch test barrel: Hornady’s 190 gr Sub-X in 300 Blackout and Hornady’s 250 gr Sub-X in 350 Legend, both at 1,050 fps. Velocity and energy follow Hornady’s published tables. Drop and wind are Chattahoochee Munitions calculations with a 100-yard zero, standard atmosphere and a 10 mph full-value crosswind.
| Range | 300 BLK 190 gr Sub-X: energy / drop / wind | 350 Legend 250 gr Sub-X: energy / drop / wind |
|---|---|---|
| Muzzle | 465 ft-lb | 612 ft-lb |
| 100 yd | 420 ft-lb / 0 / 1.3 in | 521 ft-lb / 0 / 2.2 in |
| 200 yd | 384 ft-lb / -33.4 in / 5.2 in | 457 ft-lb / -35.5 in / 8.2 in |
| 300 yd | 355 ft-lb / -104.9 in / 11.3 in | 408 ft-lb / -113.1 in / 17.9 in |
The 350 Legend’s heavier, wider subsonic bullet carries about 30 percent more energy at the muzzle and about 25 percent more at 100 yards. The longer, more streamlined .30-caliber bullet holds its speed better, so the 300 Blackout drops a little less and drifts noticeably less in wind, and the gap in energy narrows with range. In 300 Blackout vs 350 Legend hunting inside about 100 yards, both are practical subsonic hog and deer loads with a bullet designed to expand at that speed.
The differences that usually decide 300 Blackout vs 350 Legend subsonic are elsewhere. The 300 Blackout has far more subsonic loads, from 190 to 245 gr, and it burns its powder in a short barrel, so it stays compact in 8 to 10.5-inch firearms. Chattahoochee Munitions uses a 1:5 twist on those barrels so long subsonic bullets stay stable. The 350 Legend needs a suppressor rated for .357-inch bullets, a larger bore than a .30-caliber suppressor. Check the ammunition maker’s twist guidance for any subsonic 350 Legend load. Read 300 Blackout subsonic.
300 Blackout vs 350 Legend Supersonic Ballistics
The table compares Hornady’s 110 gr V-MAX in 300 Blackout (2,375 fps, 16-inch test barrel) with Hornady’s 170 gr InterLock in 350 Legend (2,200 fps, 20-inch test barrel). Downrange values are Chattahoochee Munitions calculations with a 200-yard zero, standard atmosphere and a 10 mph full-value crosswind.
| Range | 300 BLK 110 gr: energy / drop / wind | 350 Legend 170 gr: energy / drop / wind |
|---|---|---|
| Muzzle | 1,378 ft-lb | 1,827 ft-lb |
| 100 yd | 1,071 ft-lb / +3.2 in / 1.4 in | 1,282 ft-lb / +4.4 in / 2.2 in |
| 200 yd | 821 ft-lb / 0 / 6.2 in | 882 ft-lb / 0 / 9.7 in |
| 300 yd | 622 ft-lb / -13.7 in / 14.8 in | 609 ft-lb / -19.5 in / 23.7 in |
The 350 Legend’s heavier, wider bullet starts with about a third more energy, and it is measured from a longer barrel. It slows faster, so by 200 yards the two carry about the same energy, and at 300 yards the 300 Blackout drops less and drifts less. Winchester publishes its 150 gr Extreme Point 350 Legend at 2,225 fps and 1,649 ft-lb from a 16-inch barrel, which is a closer comparison to a 16-inch 300 Blackout. See 300 Blackout ballistics.
Straight-Wall Hunting Rules
This often decides 300 Blackout vs 350 Legend. Some states that once allowed only shotguns and muzzleloaders for deer now allow straight-wall rifle cartridges within set limits. The 350 Legend qualifies as a straight-wall cartridge. The 300 Blackout is a bottleneck cartridge and does not. Check your state’s current regulations, including the rules on firearm type and magazine capacity, before you hunt.
Barrel Length and Firearm Size
The 300 Blackout burns its powder in about 9 to 10.5 inches in Chattahoochee Munitions’ experience, so CM offers it in 5, 7.5, 10.5 and 16-inch CM15s and in 8, 10 and 12.5-inch CM7S bolt actions. The 350 Legend gains velocity with a longer barrel; Winchester’s figures show about 100 fps more from a 20-inch barrel than a 16-inch one. Chattahoochee Munitions offers the CM15 350 Legend with an 18-inch barrel.
Parts and Magazines
Both use an AR15 lower and a standard-size bolt face, and both need their own barrel. The 300 Blackout feeds from a standard AR15 magazine; Chattahoochee Munitions offers a CM15 300 Blackout magazine. The 350 Legend’s straight case feeds reliably from a dedicated magazine, such as the CM15 350 Legend magazine. Every CM15 uses a TriggerTech AR15 Duty trigger at 3.5 lb.
300 Blackout vs 350 Legend: Which Should You Choose?
- Choose 300 Blackout for the widest choice of subsonic loads, a .30-caliber suppressor, short barrels, a bolt-action option and hunting where bottleneck cartridges are legal. Explore Sector 300, including the CM15 300 Blackout hog hunting rifle and the CM7S 300 Blackout deer hunting rifle, and read 300 Blackout hunting.
- Choose 350 Legend for deer in straight-wall states, a heavier bullet supersonic inside about 200 yards, and more subsonic energy at short range. Explore Hall of Legends, including the CM15 350 Legend AR15, and read the 350 Legend guide.
300 Blackout vs 350 Legend FAQ
Is 350 Legend better than 300 Blackout?
For deer hunting in straight-wall states, the 350 Legend fits. For short-barrel, suppressed use with the widest choice of subsonic loads, the 300 Blackout does.
Which hits harder, 300 Blackout or 350 Legend?
The 350 Legend, at short range. Supersonic, it starts with about a third more energy, and the two are close by 200 yards. Subsonic, Hornady’s 250 gr 350 Legend load carries 612 ft-lb at the muzzle against 465 ft-lb for its 190 gr 300 Blackout load.
Is 300 Blackout legal in straight-wall states?
No. It is a bottleneck cartridge. Check your state’s rules.
Can 350 Legend be subsonic?
Yes. Factory subsonic 350 Legend loads use heavy bullets, such as Hornady’s 250 gr Sub-X at 1,050 fps from a 16-inch barrel. There are fewer of them than subsonic 300 Blackout loads.
Do 300 Blackout and 350 Legend use the same bolt?
Both use a standard AR15 bolt face, but each needs its own barrel and the correct magazine.
Can you suppress a 350 Legend?
Yes, with a suppressor rated for .357-inch bullets or larger. A .30-caliber suppressor is too small.
Which recoils less, 300 Blackout or 350 Legend?
The 300 Blackout, especially with subsonic loads. Both are mild in an AR15.
Who makes 300 Blackout and 350 Legend rifles?
Chattahoochee Munitions manufactures 300 Blackout firearms on the CM15 AR15 and CM7S bolt action, and the CM15 350 Legend AR15 with an 18-inch barrel.