So, I see you're a shooter of culture and have decided to shoot a beefier round out of your AR-15. I like that! No 5.56 NATO or 6.5 Grendel for you…Who needs all these namby-pamby intermediate cartridges anyway? Let's go straight to .45 caliber and get some work done!

However, this does pose an immediate question as to which 45-cal you want to pick up? The 450 Bushmaster or 458 SOCOM?

These two big bore cartridges give you the flexibility to turn a standard AR-15 into a deer hunting rifle, a semi-automatic hog slayer, and a heavy-hitting personal defense carbine all rolled up into one firearm.

In this article we will analyze each cartridge to help you decide how to resolve the decision between 458 SOCOM vs 450 Bushmaster.

Cartridge Specs

When evaluating centerfire rifle cartridges, it's a good idea to analyze the cartridge specs to gain more knowledge of each.

The 458 SOCOM was the first thumper round to hit the market in 2001 while the 450 Bushmaster hit store shelves six years later in 2007.

Development of the 458 SOCOM began in 2000 in response to a conversation (supposedly at a barbecue) between Marty Ter Weeme of Teppo Jutsu LLC and a member of the United States Special Operations Command (SOCOM) surrounding the ineffectiveness of the 5.56 NATO. Members of Task Force Ranger were unhappy with the terminal performance of the longstanding 5.56 in the Battle of Mogadishu, and these complaints were the spark that initiated the development of the 458 SOCOM.

The 450 Bushmaster (or 450 BM) was developed by Tim LeGendre of LeMAG Firearm. LeGendre cites Lt. Col. Jeff Cooper's writings on the Thumper concept as his inspiration for creating the 450 BM.

Perhaps the biggest difference between these two cartridges is their case design itself. The 450 Bushmaster is a straight-walled cartridge while the 458 SOCOM has a slight shoulder. Straight-walled cartridges are necessary for deer hunting in Midwest states like Ohio, Iowa, Indiana, and Michigan while the bottlenecked design aids in reliable feeding.

Although developed to achieve similar ballistic results, the 458 SOCOM and 450 Bushmaster utilize very different parent cases. A lengthened 50 Action Express, or 50 AE, was utilized for the 458 SOCOM with a case length of 1.575". The 50 AE is famous for being the primary chambering of the Desert Eagle handgun. In contrast, the 450 Bushmaster was developed using the 284 Winchester as a parent case and has a longer case length measuring 1.70".

Although their case length is different, the 450 Bushmaster and 458 SOCOM have the same maximum overall length of 2.26" as this is the longest cartridge length that can be used in an AR-15 receiver. Furthermore, the case capacity is nearly identical between these two big bore cartridges, as the 450 can hold 59.5 grains while the 458 can handle slightly more powder with a 61.1 grain capacity.

Both rounds utilize a rebated rim design, meaning their rim is narrower than their cartridge base. The 450 BM and 458 SOCOM have the same rim diameter of 0.473", which is the same as the 308 Winchester, 30-06 Springfield, and 270 Win.

Another major difference between both cartridges is the type of bullet they fire.

The 458 SOCOM cartridge fires a 0.458" bullet diameter which is more common than you might think as it is used by rounds such as the .45-70 Government, 458 Winchester Magnum, 450 Marlin, 460 Weatherby, and 458 Lott. The SOCOM round can fire bullets within a 200-600 grain range, though 250gr, 300gr, and 350gr factory loads are the most common.

In contrast, the 450 Bushmaster fires a 0.452" bullet diameter ranging between 158-300 grains with the 250 grain bullet being the most popular while the 260 gr factory loads come in at a close second. Bullets fired by the 450 Bushmaster are also fired by three popular handgun cartridges, the 45 Colt, 454 Casull, and 460 S&W.

Both rounds are generally loaded to similar pressures, but only the 450 Bushmaster is SAAMI certified with a listed maximum pressure of 38,500 psi.

Muzzle Velocity, Kinetic Energy, and Trajectory

Lt. Col. Jeff Cooper defined the "Thumper concept" as a cartridge designed to be fired from the semi-auto AR-15 rifle, having an effective range around 250 yards, was 44-caliber or larger, and could harvest big game animals with a single shot.

Without question, both rounds fit the bill in terms of integrating into the AR-15 platform and being larger than 44-caliber, but how do they stack up in terms of ballistics?

For the purposes of this comparison, we will analyze the ballistic performance of the 250 gr Hornady FTX and 300 gr Federal Power-Shok for 450 Bushmaster. For the 458 SOCOM, the Barnes 300-grain TTSX loaded by Buffalo Bore and the SBR Precision Ammunition 450 gr FMJ factory loads were selected.

In the chart below, we will compare muzzle velocity, kinetic energy, and bullet drop for each cartridge out to 300 yards assuming a 100 yard zero.

Although the 458 SOCOM has slightly higher case capacity, the lower bullet weights fired by the 450 Bushmaster generally surpass those fired by the 458 in terms of muzzle velocity. The 250 gr FTX load fire by the 450 comes in as the fastest round analyzed at 2,200 fps while both 300 grain loads had the same muzzle velocity of 1,900 fps. Not unsurprisingly, the heaviest bullet, the 450 gr FMJ 458 SOCOM load, had the slowest muzzle velocity at 1,450 fps.

In terms of muzzle energy, the 250 gr FTX 450 Bushmaster cartridge continues to outperform at 2,687 ft-lbs, followed by the two 300 gr bullets at 2,405 ft-lbs.

Although there are minor differences between these four rounds, all of them have similar performance out to 150 yards in terms of trajectory. However, once we move past 200 yards we see the two rounds start to separate as the 458 SOCOM starts to dip closer and closer to the subsonic velocities.

At 300 yards, the 250 gr FTX and 300 gr TTSX loads are still supersonic (barely), while the 300 gr Power-Shok and 450 gr FMJ loads have dipped below the speed of sound.

It should be noted that neither of these rounds are incredibly flat shooting. However, the lighter 450 Bushmaster loads give you the flattest trajectory and will typically stay supersonic out to and past 300 yards.

In terms of effective range, hunters generally consider 1,000 foot-pounds of kinetic energy the minimum amount required for harvesting a whitetail and 1,500 foot-pounds for elk or other larger game. With this in mind, the 450 Bushmaster and 458 SOCOM have an identical effective range of 250 yards for deer and 150 yards for elk when considering non-FMJ bullets.

Recoil

There's a reason why this class of rifle cartridges are known as "thumper rounds". Not only do they hit hard on large game, but they impart stout recoil on the shooter's shoulder as well.

Felt recoil will differ from shooter to shooter and is dependent on shooting position, stance, and the firearm being used. However, free recoil can be used to give a general idea of how hard a round kicks.

Free recoil is dependent on bullet weight, rifle weight, muzzle velocity, and powder charge. To provide a clean "apples to apples" comparison, a standard AR-15 carbine weight (7.5 lbs) will be used for each calculation.

This may not be completely accurate in terms of real-world experience, as AR-15 rifle barrel weights can vary depending on the contour and manufacturer. However, the chart below will give you a general idea of how much recoil each cartridge imparts on the shooter.

In general, the 450 Bushmaster will have slightly less recoil than the 458 SOCOM. However, with recoil this heavy, most shooters won't be able to discern any major difference between the two.

The bottom line is that both cartridges have heavy recoil and are not suitable for recoil-sensitive shooters without proper training and acclimatization.

Ballistic Coefficient and Sectional Density

Ballistic coefficient (BC) is a measure of how aerodynamic a bullet is and how well it will resist wind deflection. Sectional density (SD) is a way to evaluate the penetration ability of a bullet based on its external dimensions, design, and weight.

Typically, longer and heavier bullets will have a higher BC as they can resist wind drift more efficiently. Each of these rounds are limited in their design capabilities due to the restrictions of the AR-15 platform.

Restricting the maximum overall length of a cartridge to 2.26" and demanding kinetic energy values over 2,000 ft-lbs means that bullet design must take a back seat to external ballistics. Therefore, short and thick bullets have to be used instead of more aerodynamic ones.

Generally, the 458 SOCOM will have a higher BC than the 450 Bushmaster since the 458 can fire heavier bullets. For example, the 300 gr SST 458 SOCOM has a BC of 0.236, followed by the 250 gr XTP 450 Bushmaster at 0.21.

In terms of penetration, the SOCOM measures higher at 0.204 compared to 0.175 for the 450 BM.

It is unlikely that the whitetail or hog in your sights will be able to detect any differences in penetration. However, all things being equal, the 458 will penetrate just a bit deeper than the 450.

Hunting

When it comes to big game hunting, the 458 SOCOM and 450 Bushmaster are excellent options within their effective range.

The 450 Bushmaster is an excellent deer hunting options in states that require the use of straight-walled cartridges. On the other hand, the 458 SOCOM offers similar ballistic performance to the 450 Bushmaster with heavier bullets.

For larger game like elk and moose, the 458 SOCOM makes a lot of sense as fires a wider diameter bullet, thereby increasing the size of the wound channel and is an incredibly hard-hitting cartridge.

For hogs, coyotes, and general pests you can't go wrong with either one. The 458 SOCOM is typically favored for feral hogs thanks to its bottle-neck cartridge design and the devastating 300 gr Barnes TTSX bullet that was specifically designed for this purpose. The 450 BM is more than lethal enough for hogs, hunters just typically don't restrict themselves to straight-walled cartridges unless they have to.

Neither the 450 Bushmaster nor 458 SOCOM is particularly useful for varmint hunting due to their heavy recoil. That's not to say that you CAN'T use them for this purpose, just most hunters prefer something with lower recoil for these pesky critters. Usually rounds like the 223 Remington are preferred for varmint hunting as it has low recoil, is very flat shooting, and inexpensive.

Ammo and Rifle Cost/Availability

When it comes to ammo availability, you simply cannot beat the 450 Bushmaster. It is unquestionably is the easiest to find factory ammo for as it is SAAMI certified and therefore larger ammo manufacturers like Hornady, Remington, Winchester, Barnes, and Federal make ammunition for it. On the other hand, only custom ammo manufacturers like SBR, Underwood Ammo, Buffalo Bore, and Black Butterfly make 458 SOCOM rounds regularly.

For 450 Bushmaster ammo, inexpensive Remington UMC factory loads can be had for as low as $1.50/round while premium hunting ammo like Federal Fusion or Barnes VOR-TX will cost around $3/round and up.

For the 458 SOCOM ammo, less expensive factory loads from Underwood can be had for around $2/round while bear hunting hard cast loads from Buffalo Bore run upwards of $5/round.

In terms of factory rifle availability, there are considerably more options for the 450 Bushmaster compared to the 458 SOCOM.

For the 458, the most common options available are AR-15 rifles from manufacturers like Tromix, Wilson Combat, and Bear Creek Arsenal (BCA). In contrast, since the 450 is SAAMI certified, there are considerably more rifle options including bolt-action rifles like the Ruger American and Savage 110.

However, as any AR-15 rifle is a potential host with a simple barrel, bolt, and magazine swap, this means there are tons of potential host rifles on the market for both cartridges.

Reloading

Although factory loads can be a little pricey for these big bore AR rounds, handloading is one method shooters utilize to reduce their overall cost per round.

All of the major bullet manufacturers like Barnes, Hornady, Nosler, Sierra, and Federal have multiple bullet options available for both calibers. This allows hand loaders the flexibility to create rounds that are customized to their rifle and their unique shooting needs.

Sourcing reloading dies is simple enough for the 450 and 458 as Lee and Redding both have die sets for each caliber.

It should be noted that it is not advised to use 45 ACP handgun bullets for reloading the 450 Bushmaster. Jacketed 45 ACP bullets measure 0.451" in diameter while the 450 Bushmaster requires the slightly wider 0.452" diameter bullets. Although the smaller 0.451" diameter bullets can be handloaded safely, you will likely see decreased performance and accuracy as the bullet may not completely engage the rifling in the barrel.

Final Shots: 450 Bushmaster vs 458 SOCOM

The 450 Bushmaster and 458 SOCOM are two big bore cartridges that add a lot of stopping power to the AR-15 rifle. Designed for shots within 250 yards or less, these three rounds deliver crippling kinetic energy that can transform any AR-15 into a capable hog and deer hunting rifle.

The 450 Bushmaster is an excellent deer hunting options for Midwest states that require the use of straight-walled cartridges. The 450 Bushmaster is also unique in the fact that there are single shot and bolt-action rifles available for hunters that are required to use these firearms whereas the 458 is currently relegated to the AR-15 platform only.

For big game animals like elk, black bear, and even moose, I'd favor the 458 SOCOM primarily due to the Barnes 300gr TTSX bullet as it was designed specifically for this cartridge. This bullet is absolutely devastating to large game so long as your shot placement is on point.

Selecting the right thumper round for your needs primarily revolves around your local hunting regulations, the type of game you want to hunt, and the ranges you expect to shoot at.

Regardless of which cartridge you choose, make sure you get all your ammunition here at Ammo.com and get out to the range so you are always ready to defend freedom should the need arise.

450 Bushmaster vs 458 SOCOM: Some Shooters Like It Bigger originally appeared in The Resistance Library at Ammo.com.