The Comparison of the Big Bore Cartridges: 450 Bushmaster vs. 45-70

Not everyone is such a loyal follower of trends in the shooting industry to acquire only modern and up-to-date weapons and cartridges. In this overview, we will analyze and present you with two big bore rounds, different in every aspect but with the same ability to take the large game out to 250 yards.

One cartridge comes from the romanticized “Wild West” period in American history and the other spawned from the harsh reality and need to penetrate barriers better than an AK47.

450 Bushmaster Vs. 45-70
Cartridge450 Bushmaster45-70 Government
Bullet240 to 350 gr (15.5 to 22.7 g)250 to 500 gr (16.2 to 32.4 g)
Bullet diameter0.452” (11.48 mm)0.458” (11.65,7 mm)
Case length1.700” (43.18mm)2.105” (53.5 mm)
Maximum overall length2.25” (57.15 mm)2.55” (64.8 mm)
Rim diameter0.473” (12.01 mm)0.608” (15.4 mm)
Max Pressure (SAAMI)38,500 psi28,000 psi
Muzzle Velocity300 gr/ 1,900 fps405 gr/1,350 fps
Muzzle Energy300 gr/ 2,405 ft-lbs.405 gr/ 1,639 ft-lbs.
            400yds Bullet Drop & Energy-78.0” 644 ft-lbs.-162.6” 798 ft-lbs.
Powder load250 gr/ 40.4 gr405 gr/ 29.0 gr 325 gr/ 49.1 gr
Rifle Weight7.0 lbs.7.0 lbs
Free recoil energy250gr/25.62 ft-lbs..405 gr/20.75 ft-lbs. 325 gr/ 37.66 ft-lbs.
Case capacity59.5 gr H2O81.8 gr H2O

.45-70 Government – A Bit of History and Specs

When the guns fell silent after the American Civil War, the U.S. Army started looking for new breech-loading rifles and cartridges using metallic cases to replace the muzzleloading rifles and paper cartridges.

The development was entrusted to the U.S. Government’s Springfield Armory and initially, they developed the single-shot Springfield Model 1866 breech-loading rifle chambered for the .50-70 Government cartridge. Soon after, the Springfield Armory released an improved version of this rifle/cartridge combination and called it the Springfield Model 1873 or the “Trap Door Springfield,” In contrast, the cartridge was dubbed .45-70-405, adhering to the standard naming convention at the time. It translates that the cartridge was loaded with a .45 caliber bullet over a powder charge of 70 grains of black powder and used a 405-grain bullet for the cartridge.

When the U.S. Army adopted a couple more ballistically efficient loads like 500-grain bullets, they changed the designation to a .45-70 U.S. Government. Later the official military designation was simplified to .45-70 Government and abbreviated to .45-70 Govt or just .45-70. As one of the very first centerfire rifle cartridges, the .45-70 Government was an extremely potent round, particularly when compared to primitive muzzleloading rifles loaded with cartridges wrapped in paper.

The initial .45-70 round fired a 405-grain projectile with a muzzle velocity of roughly 1,200fps and was considered effective to about 300 yards.

The original Trapdoor Springfield rifle Model 1873 was loaded with cartridge using a 0.458″ diameter bullet made of hard cast lead and was in the U.S. military until the late 1800s and early 1900s when the Army adopted the “Krag–Jørgensen” model 1892 rifle.

Although retired from the military service, with the development of the new smokeless propellants, the .45-70 was painlessly transitioned from black powder loads to new smokeless ones and regained sheer popularity in the civilian gun community.

After the Second World War, the .45-70 Government had again disappeared from the big game hunting scene. Still, with a new age, it revived as a phoenix and quickly became a favorite cartridge among big game hunters and CAS/OWSS enthusiasts in the United States.

The primary external features of the .45-70 Government cartridge are a rimmed, straight-walled copper case topped with a round-nosed or flat-tipped bullet.

Often called the “Flying ashtrays,” these traditional bullets aren’t very aerodynamic and deliver poor downrange performance. Modern constructions like Hornady’s “LEVERevolution” also utilize bullets with a pointed, flexible polymer tip.

Though using Hornady’s LEVERevolution ammunition with a pointed tip provides higher velocity, a slightly flatter trajectory and retains more energy with a bit longer effective range, you cannot compare it to the modern stuff like the 7mm Rem Mag or .300 Win Mag.

However, it is pretty easy compared to the .450 Bushmaster because their ballistics are even closer than you might think. Both cartridges have very similar performance with some overlap in their capabilities.

However, the .450 Bushmaster has a significant advantage over the low-powered .45-70 loadings intended for use in the old “Trapdoor Springfield,” but it can’t reach the performance of the superior .45-70 LEVERevolution loads.

Though the 2.105” long and wide case (.504″) has massive case capacity, the factory loads use less smokeless powder to keep the pressure low for safety in antique rifles and their replicas. However, the new production rifles like the Marlin 1895 and the Winchester 1886 aren’t limited by the strength of the firearm chamber, making them capable of handling higher pressure loads.

For safety reasons, ammunition manufacturers offer .45-70 ammo in different power levels for use in rifles from a different eras. That said, we have .45-70 Govt offerings with three levels of maximum pressures designed for safe use in specific firearms.

The low-pressure or “reduced pressure” loads are designed for use in vintage Trapdoor Springfields and its authentic replicas (15,000-18,000psi). The higher-pressure loads are intended for use in modern 1886 Winchester and Marlin 1895 rifles (22,000-28,000psi) and some ammo companies making magnum loads that are only safe to use in some lever actions, falling block actions like a Ruger No. 1 and Siamese Mauser bolt actions (30,000-39,900psi).

450 Bushmaster history – A Bit of History and Specs

When looking for ‘big-as-your-thumb’ cartridges, the .450 Bushmaster is a mandatory part of every research. This relatively new big-bore cartridge is a part of the big round-up designed for use in an AR-15 platform rifle. Unlike the venerable .45-70 Government.

Designed according to Col. Jeff Cooper’s “Thumper” concept of rifle-cartridge capable of one-shot kills on big game animals at 250 yards, the .450 Bushmaster delivers a bone-crushing performance.

The straight-taper .450 Bushmaster (sometimes dubbed the .450 B.M. for short) was initially developed in 2007 by Timothy LeGendre of LeMag Firearms Company. The parent cartridge was a .45 Professional, which later was redesigned and shortened by Hornady to accommodate its 250-grain pointed SST bullet.

Let’s compare physical similarities between the .45-70 Government and 450 Bushmaster. Except for the straight-walled case and approximately identical bullet diameter (but not the same). These two rounds don’t have any other common traits.

Though the .450 Bushmaster and .45-70 Government use .45 caliber bullets, these are not of the same diameter. The .45-70 is loaded with .458” rifle bullets, and the .450 Bushmaster uses slightly modified .452″ caliber pistol bullets. These smaller diameter and lighter pistol bullets are less tough than heavier and more solidly constructed .45-70 rifle bullets.

While the .45-70 Government fires larger diameter bullets weighing in the 250gr to 540 gr range, most .450 Bushmaster ammo comes in the 158gr to 300 range, whereas most Bushmaster factory loads use 250gr and 260 gr bullets.

 A few authors describe Bushmaster as a .223 on steroids or a light, semi-auto .45-70 caliber round. However, this hard-hitting .45 caliber cartridge is undoubtedly able to cleanly and ethically take bigger game than deer, mainly when using the newest generation of hunting ammunition.

Both are straight-walled cartridges, but the .450 Bushmaster has a shorter overall length, a shorter case length, and a narrow diameter case than the

.45-70  due to the constriction of an AR-15 action. Namely, the.450 Bushmaster cartridge has entire length of 2.25″ and a 1.7″ long case, whereas the .45-70 has entire length of 2.25″ and a 1.7″ long case.

Speaking of ethical and human hunting, neither the .45-70 nor the .450 Bushmaster is a good choice for hunting situations at ranges over 200 yards. Still, both rounds have proved deadly on Black Bear and the deer-sized game, even at 300-yards bearing more than 900 ft/lbs. of energy.

However, the .45-70 with longer rifle bullets has a bit of an edge in retained energy since the Bushmaster fires big, heavy, short bullets with an inferior aerodynamic design.

The typical hunting range for both cartridges is between 150-200 yards, but the effective range is probably closer to 400-500 yards. The .450 Bushmaster may have a bit of an edge in accuracy potential with modern loads.

Speaking of recoil, both of these big-bore cartridges have heavy recoil. While the low-pressure .45-70 loads have surprisingly low recoil, the modern higher-pressure .45-70 loads have about 47% more recoil than the .450 Bushmaster load. The .450 Bushmaster, on the other hand, with typical loads, has recoil on par with cartridges like the .30-06 Springfield or 7mm Magnum.

Final thought

Undoubtedly, the .45-70, as a part of American history, retains excellent popularity among American sportsmen and gun enthusiasts. Even today, loaded with modern smokeless powders, the .45-70 Government is an excellent deer and hog hunting round, particularly for those who use lever-action rifles.

Compared to the .45-70, the much younger .450 Bushmaster is a light recoiling cartridge capable of good accuracy within reasonable hunting distances.

While both cartridges aren’t really known for precision shooting, both will take down a big game with authority in thick woods or heavy cover where shots below 100 yards are common.

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