Another in our series of caliber wars -- this time the older 300 BLK against the brand new (kind of) 350 Legend!
One designed for combat, the other for sporting, both of these AR-15 calibers are solid deer harvesting options -- but what is better?
We’ll dive into that and a whole lot more!
Design Intentions
350 Legend
One of the newest cartridges around, .350 Legend was released in Jan of 2019 from Winchester as a straight-wall mid-range deer slayer.
While named 350, the caliber is actually .357 and is thus legal in all of those odd states that still require a straight-walled rifle cartridge -- Michigan, Ohio, Iowa, and Indiana.
Why they require it is really just beyond my ability to understand, but at least they aren’t requiring shotgun and muzzle-loader only like they used to.
350 Legend was designed from the ground up to be able to serve those hunter’s needs. This is one of the purest sporting cartridges around today.
300 Blackout
On the other hand, 300 Blackout was more designed for combat than it was for hunting.
The design intent was for a .30-caliber cartridge that shared as many parts with the standard M4 as possible and didn’t sacrifice any magazine capacity.
Mimicking 7.62x39 Soviet ballistics and functioning both in sub-sonic and super-sonic, 300 BLK was built to be a quiet, deadly, warfighting cartridge.
While it fills that role wonderfully, it also is a really good sporting cartridge.
For hunting hogs, deer, or home defense -- 300 BLK is a solid option.
Ballistics
When it comes to similar bullet weights and supersonic ammo, there really isn’t much difference between the 350 Legend and 300 Blackout ammo.
Bullet weights aren’t totally 1:1 but they are pretty close.
The most common 350 Legend weight is around 160-170gr FTX. 300 BLK supers come in a wide range of options, but 150gr is super common.
Side-by-side… they are really basically the same.
Both are solid deer killers out to around 200 yards, but 300 BLK can go with a lighter bullet weight and push that to about 300 yards.
The drop is more or less the same within a few inches, lethality goes to 350 Legend but only because 300 BLK shines at a slightly lower bullet weight than 150gr.
Practical Applications
300 Blackout was designed as a combat cartridge, but it also has found a role in home defense and hunting. Ammo selection is great in both super- and sub-sonic while being easy to find in basically every LGS.
Something 300 BLK was designed for also is to work great suppressed, this it does very well and is one of the best AR-15 cartridges to throw a can on.
Able to take deer-sized game out to about 300 yards, 300 BLK is a solid all-round choice.
350 Legend on the other hand is a hunting cartridge, pure and simple. Subsonic ammo for 350 Legend is almost non-existent, and ammo selection, in general, is kind of poor since Winchester is basically the only brand that makes it.
Ammo is easy to order online, but finding it in-store can be very hit-and-miss -- even in straight wall cartridge states.
That said, this is a great deer dropper. Inside 250 yards, 350 Legend will harvest a deer in 1 clean hit.
[To learn more about Hunting with an AR-15, see our complete guide!]
Converting From 5.56 NATO
Shocking, the conversion process from a 5.56 NATO AR-15 (or any other AR-15 that uses a standard bolt) is the same for both 350 Legend and 300 BLK.
The easy method is a new upper. Take the old one off, throw the new one on, and you’re good to go.
But if you want to convert an upper all you need is a new barrel.
Both 350 Legend and 300 BLK use a standard AR-15 5.56 NATO bolt and bolt carrier. 300 Blackout works great in 5.56/223 magazines while 350 Legend works best in dedicated 350 Legend magazines. Just a barrel swap and grab a new mag and you’re ready to hit the range!
And The Winner Is…
Unless you’re in a straight-wall state, there really isn’t a great reason to get 350 Legend. 300 BLK can do everything 350 Legend can do plus a whole lot more and is cheaper, easier to find, and has a lot deeper selection. [See our Cheapest Ammo by Caliber 2022 infographic.]
Ballistics are so close together that there really isn’t a critical advantage to 350 Legend.
But if you are one of those midwest souls that just have to have a straight wall, then 350 Legend is a clear choice.
350 Legend is a great cartridge and serves the niche it was designed for very well. That might be basically all it does, but it does it well.
Wrapping Up
In the end, both of these are great calibers, but one is definitely a lot more flexible and useful than the other.
However, if you’re suffering under the oppression of legal constraints that make no sense -- then you do what you gotta do. As a gun nut living in California, I get it. A less-than-perfect work-around is better than nothing.
[We'd like to extend a huge thanks to David Lane for his hard work on this article! For more helpful guides check out 6.5 Creedmoor and 7.62x39 vs 5.56.]
