Are you tired of only being able to use your AR-15 on small game and for target shooting?
Good news! There are several cartridge options compatible with the AR-15 platform that offer the stopping power needed to be used on big game. The best part is that you’ll only need a new upper receiver for your AR-15 to upgrade.
Let’s dive in and see which one is right for you in detail, but here's a quick snapshot of these two calibers:
TL;DR: 450 Bushmaster vs 458 SOCOM
Easier to find factory loads
Can use heavier bullets (up to 600 grains)
More effective hunting range (250 yards)
Compatible with standard 5.56mm NATO magazines and many aftermarket 5.56/.223 magazines
Large variety of bullets/bullet molds for reloading
Fewer bullet weight options
Hard to find factory loads
5.56mm magazines may need modification to be compatible
Less effective hunting range (~150 yards)
Deer, hog, and elk hunters who prefer the AR-15 platform, are willing to sacrifice some stopping power for increased range and plan to buy factory ammo.
Big game hunters and guides who need a weapon with plenty of stopping power, who hunt in areas where shots are generally taken within 150 yards, and who are reloaders or planning to be.
What is the .450 Bushmaster?
The .450 Bushmaster is a rifle cartridge that was designed to be a big bore alternative to the 5.56x45mm NATO fired from the AR-15 platform. This idea was inspired by the Thumper concept which was conceived by US Marine and firearms instructor Jeff Cooper. Following this concept, a round like the .450 Bushmaster would be able to provide one-shot kills on the big game out to a range of 250 yards.
The .450 Bushmaster can be fired from standard AR-15 rifles equipped with modified magazines and upper receiver assemblies providing big game hunters with improved stopping power from the popular and easy-to-shoot AR-15 platform.
Using a 250-grain bullet, a .450 Bushmaster round travels more than 2,200 feet per second and has over 2,700-foot-pounds of energy. With a zero of 150 yards, hunters can expect a drop of about 4.9 inches at 200 yards which makes the .450 Bushmaster relatively flat shooting.
This cartridge will fit single stacked in standard AR-15 magazines equipped with a single stack follower. Another great perk of the .450 Bushmaster is that it is considered legal for deer hunting in states that require straight-walled cartridges for such hunting. (Always check your local laws and regulations before hunting.)
What is the .458 SOCOM?
The .458 SOCOM is another rifle cartridge derived from the Thumper concept developed by Jeff Cooper. Its main goal is also to provide hunters with a big bore alternative to shoot from the AR-15 platform to provide one-shot kills on big game such as deer, hogs, and elk. Originally designed for the military and then gaining popularity among hunters, the .458 SOCOM greatly expands the usefulness of the AR-15 platform in the hands of a big game hunter.
Using a 250-grain bullet, the .458 SOCOM has a muzzle velocity of 2,150 feet per second and has 2,565-foot-pounds of energy. This cartridge can be used with bullets of up to 600 grains which provides more options for different types of hunting scenarios. If used with a 600-grain bullet, this round has a muzzle velocity of 1,000 feet per second and has 1,336-foot-pounds of energy.
One benefit to the .458 SOCOM is its ability to be loaded with many different sizes of bullets ranging from 140 grain to 600 grain. This is especially important to note for reloaders as it increases their options. Another great perk of the .458 SOCOM cartridge is that it will load into standard NATO 5.56 magazines without any modifications.
The .458 SOCOM is also legal in some states to use for deer hunting, but always check your local laws and regulations to make sure.
Relevant Characteristics: 450 Bushmaster vs 458 SOCOM
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2,214 ft/s (w/ 250 gr SST)
Velocity (at muzzle)
2,150 ft/s (w/ 250 gr SP)
2,722 ft-lbf (w/ 250 gr SST)
Energy (at muzzle)
2,565 ft-lbf (w/ 250 gr SP)
Acceptable Bullet Sizes
Maximum Range (for ethical hunting)
Similarities and Differences
At this point, you may still be a little confused on exactly what makes these rounds similar and what sets them apart from each other. Let’s dive in a little deeper and take a look under the hood to figure out the similarities and differences between the .450 Bushmaster and .458 SOCOM cartridges.
450 Bushmaster and 458 SOCOM Differences
One of the main, and most important, differences between the .450 Bushmaster and the .458 SOCOM is the size of the bullets that can be used in each load. The .450 Bushmaster cartridge can accommodate bullets from 245 grains up to 300 grains. On the other hand, the .458 SOCOM has a larger range available with bullets from 140 grains all the way up to 600 grains being used. If you are a reloader, the .458 SOCOM may appeal to you more because of the larger range of bullet options.
Another big difference between these two cartridges is the maximum effective range for ethical hunting. The .450 Bushmaster can take a big game out to a maximum range of 300 yards although most hunters will feel more comfortable making 250 yards their maximum range. The .458 SOCOM has a much shorter max range of about 150 yards.
This is also dependent on the bullet weight used in a round. Heavier bullets are going to drop like a stone as they travel down range. The .458 SOCOM and its shorter range would make for an excellent option when hunting something like hogs in brush-covered areas where shots tend to be shorter. A .458 SOCOM cartridge with a heavier bullet (up to 600 grains) would also make a solid guide gun or bear protection rifle.
450 Bushmaster and 458 SOCOM Similarities
Despite their differences, the .450 Bushmaster and the .458 SOCOM are very similar cartridges. Their similarities extend beyond the fact that they both rose out of the Thumper concept.
The .450 Bushmaster and .458 SOCOM are both big bore cartridges that have a lot of power. When using the same weight of the bullet, both of these cartridges are very similar powerwise. Obviously, this doesn’t hold true when using some of the larger bullet weights the .458 SOCOM is capable of using.
In the case of using a 250-grain bullet, both of these cartridges are within 157-foot pounds of energy at the muzzle. The .450 Bushmaster produces 2,722 foot-pounds at the muzzle while the .458 SOCOM produces 2,565-foot-pounds at the muzzle.
To really understand how much power this is, keep in mind that a common 55 grain .223 Remington cartridge produces 1,280-foot-pounds of energy.
The .450 Bushmaster and the .458 SOCOM can both be used effectively on big game animals including hogs, deer, elk, and black bears.
Velocity is another area where these two cartridges are similar. Again, keeping in mind that this applies to cartridges loaded with 250-grain bullets. The heavier bullets that can be used in the .458 SOCOM are slower.
With 250 grain bullets, the .450 Bushmaster (2,214 ft/s) and .458 SOCOM (2,150 ft/s) are within 64 feet per second of each other in velocity at the muzzle. Both of these cartridges are slow when compared to a 55 grain .223 Remington cartridge which has a muzzle velocity of 3,240 feet per second.
The lack of speed limits the effective hunting range, but the larger amount of energy increases the ability to make one-shot kills on big game with both the .450 Bushmaster and .458 SOCOM.
One other notable way that these two big bore cartridges are similar is the fact that they can both be used with standard 5.56 x 45mm NATO magazines. Both of these cartridges measure 2.26 inches in length which is exactly the same as 5.56 x 45mm NATO (.223 Remington) cartridges.
These magazines obviously won’t have the same capacity they have for 5.56 x 45mm NATO cartridges. This is because both the .450 Bushmaster and .458 SOCOM only fit into these magazines in a single stack whereas 5.56 x 45mm NATO cartridges use a double stack configuration.
Some magazines will require the standard follower to be changed out to a single stack follower to hold the big bore rounds, but you won’t have to buy all new magazines for .450 Bushmaster or .458 SOCOM cartridges.
Advantages of the 450 Bushmaster
Here are some advantages of 450 Bushmaster:
Longer Effective Range
One of the biggest advantages of the .450 Bushmaster is the longer effective range it offers hunters. Considering the straight-walled nature of the cartridge allows it to be used for hunting in many states that don’t typically allow hunting with rifles, that extra range can really help hunters fill their tages. An extra hundred yards or so of reliable range greatly increases the likelihood of bagging that trophy buck or mature elk that always seem to hang up just out of range of shotguns and bows.
Store Bought Ammo
It can be a challenge to find ammo for just about any firearm these days. The .450 Bushmaster, and other big bore rifle cartridges, are not immune to that challenge. If you are not a reloader and plan to only purchase ammo from a gun store or over the internet, the .450 Bushmaster will be a better choice.
While it still isn’t always in stock, ammo for the .450 Bushmaster does tend to be easier to find. Large ammo manufacturers such as Hornady, Federal, Remington, and Winchester all make factory loads for the .450 Bushmaster. On the other hand, .458 SOCOM remains more of a niche cartridge and isn’t manufactured on as large of a scale.
Both the .450 Bushmaster and .458 SOCOM are popular rounds to reload due to the relative scarcity of factory ammo and the typically high prices it brings. One reloading advantage the .450 Bushmaster has over the .458 SOCOM is the fact that .45 Colt, .45 ACP, and .45/70 bullets can be used in .450 Bushmaster loads.
Reloaders can also use .284 Winchester brass to make .450 Bushmaster brass. Having the ability to use such common bullets in the reloading process opens the door to a plethora of bullet styles and casting molds for custom ammo designed for specific needs and uses.
The .450 Bushmaster is the superior choice for some shooters when compared to the .458 SOCOM. The longer effective hunting range, availability of factory ammo, and bullet options for reloading make the .450 Bushmaster ideal for hunters, especially those in states that allow hunting with straight-walled cartridges in rifles, people who want to only use factory ammo, and reloaders who like a lot of bullet mold options.
The .450 Bushmaster is the best round to choose if you are a hunter in a state that doesn’t allow hunting with rifles that use bottleneck style loads and are someone who wants good stopping power out to 250 yards from the AR-15 platform.
Advantages of the 458 SOCOM
Here are some advantages of 458 SOCOM:
The .458 SOCOM can use bullets that weigh up to 600 grains. A .458 SOCOM load using a 600-grain bullet has a devastating amount of stopping power. The trade-off for this increase in stopping power comes in the form of a reduced effective range for hunting. However, if your shots while hunting doesn’t usually go much past the 150-yard range (looking at you dense brush hunters, guides, and hog hunters) then the trade-off will be extremely worth it for you.
With a psi of 35,000, the .458 SOCOM produces less pressure than the .450 Bushmaster. This becomes a beneficial feature if you are a reloader because it is a lot easier on brass. You can easily reload brass for the .458 SOCOM several times without any ill effects. It should go without saying, but I’ll say it anyways. Always use best practices when reloading and refer to official authorities on the subject if you aren’t quite sure about something.
One of the best things about choosing the .458 SOCOM as your big bore AR-15 cartridge is the fact that standard 5.56mm NATO magazines hold .458 SOCOM rounds without any modifications. This also applies to many aftermarkets 5.56/.223 magazines as well. A 20-round 5.56mm NATO magazine will hold 7 .458 SOCOM rounds in a single-stack configuration. Having magazines that work with several different cartridges can save shooters a decent amount of money.
If stopping power is the name of the game for your hunting needs, then the .458 SOCOM is the best choice for you. This is especially true if you are a reloader or are planning to be. Ammo for this round can be hard to find as a factory load, so reloading will save you time, money, and frustration. Using bullets weighing up to 600 grains, the .458 SOCOM will stop just about any game in its tracks as long as shots are kept to an ethical range of about 150 yards or less.
What About The 45-70?
Utilizing 70 grains of black powder and a 405-grain bullet, the original 45-70 cartridge obtained a velocity of 1350 feet per second and generated 1600 foot-pounds of energy at the muzzle. Considering that this cartridge was developed in 1873, it isn’t hard to understand why it became so popular amongst hunters and outdoorsmen of the time.
The performance of the 45-70 has greatly improved from those early days of its development. Modern bullets and propellants, along with technology advancements in how rifles and cartridges are designed and manufactured, have made today’s 45-70 cartridges comparable to other Thumper concept big bore cartridges.
Here is a brief look at how modern 45-70 cartridges perform on the range.
Muzzle Energy (Foot Pounds)
Jacketed Soft Point
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The table clearly shows just how similar modern 45-70 ammunition is to both the .450 Bushmaster and the .458 SOCOM. In fact, the 45-70 can also be used for the same purposes. Big game animals can be taken down with one shot from a 45-70 at ranges up to around 200 yards.
The 45-70 isn’t going to win any races against speedy varmint loads such as the .22-250. However, it still has plenty of velocity to easily make shots on game out to around 200 yards. Considering the weight of the bullets used in 45-70 loads, approaching 2000 feet per second is still very impressive.
Two hundred yards is a relatively short distance on the modern shooting range, but the 45-70 is best kept for shots at that range or closer. It just wasn’t designed to be effective at longer ranges. The trajectory is simply much too steep with close to three feet of bullet drop between 200 and 300 yards. There is just too much risk of only wounding game animals with that type of drop.
The .450 Bushmaster and the .458 SOCOM were both born from the Thumper concept that sought to fill the need for increased stopping power and one-shot kills on big game from the AR-15 platform within a range of 250 yards. Both cartridges easily fulfilled those requirements and are now popular among hunters who want to use the AR-15 platform in more hunting scenarios.
The .450 Bushmaster offers some extra range and plenty of stopping power for deer, hogs, elk, and other big game out to about 250 yards. The .458 SOCOM doesn’t boast as much effective hunting range, but can greatly increase one-shot kill potential on big game with the use of heavier bullets that can’t be used in the .450 Bushmaster.
Aside from some minor differences, you really can’t go wrong with either one of these big bore cartridges for use in an AR-15 platform.