45-70 Ballistics
This is a two part article. The top is a history on the .45-70 and ballistics chart, the second deals with Black powder .45-70 Government Rifles.
The 45-70 dates back to as early as 1865 but it wasn’t standardized until 1873 when a U.S. Government contract was issued for several thousand Springfield rifles chambered for the 45-70. At that time it was called the 45-70 Government cartridge.
The .45-70 rifle cartridge, also known as .45-70 Government, was developed at the U.S. Army’s Springfield Armory for use in the Springfield Model 1873 centerfire rifle. The cartridge is completely identified as the .45-70-405, but was also commonly called the “.45 Government” cartridge in commercial catalogs.
The nomenclature of the time was based on several properties of the cartridge: .45″ caliber bullet diameter, 70 grains of black powder and 405 grain bullet weight.
After the 45-70 Sandy Hook tests of 1879, a new variation of the .45-70 cartridge was produced, the .45-70-500, which fired a heavier 500 grain bullet. The heavier 500 grain bullet produced significantly superior ballistics.
The 45-70 Government cartridge is beyond 130 years since its introduction and sales for this cartridge are now ever growing. Simply put, the 45-70 Government is a wonderful big bore cartridge, chambered in a newer lever action or single shot rifle like the Sharps Model 1874, where loads can be worked up to higher pressure levels it is powerful enough for all of north America’s big game animals.
Here is a Henry Lever Action in .45-70:
The 45-70 Government is a heavy hitter able to handle bullet weights up to 500 grains at speeds up to, depending on the rifle used, 1,800 feet per second (Ruger #1 Single Shot) is the heaviest built action for this cartridge. The recoil is quite substantial from the 45-70 cartridge.
Hornady has been making ammunition that boosts the performance level of many older cartridges such as the .45-70 Government. Hornady’s .45-70 Government 325 grain flex-tip bullet in their LeverEvolution ammunition (shown above) line sports a ballistic coefficient of .230 and is loaded to a velocity of 2,050 feet per second with 3,032 foot pounds of energy at the muzzle of a 24″ rifle barrel.
This gives excellent ballistics for the .45-70 Government out to 250 yards for hunting in north America with a remaining bullet energy of 1,277 foot pounds. Note: Hornady’s patented Flex Tip (FTX) bullets are safe to shoot in tubular magazines rifles.
45-70 Ballistics:
| This is a ballistics chart for the 45-70 Government rifle: | |||||||
| Rifle barrel length: 24 Inches. Ammunition: Hornady 250 grain Monoflex bullet. Bullet diameter: .458 inch. Bullet weight: 250 grains. Bullet ballistic coefficient: .175. Rifle zero: 135 yards, 2″ mid-range rise. |
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| Range | Muzzle | 25 yds. | 50 yds. | 75 yds. | 100 yds. | 150 yds. | 200 yds. |
|---|---|---|---|---|---|---|---|
| Bullet Velocity: | 2,025 fps. | 1,916 fps. | 1,812 fps. | 1,712 fps. | 1,616 fps. | 1,439 fps. | 1,285 fps. |
| Bullet Energy: | 2,276 ft.lbs. | 2,038 ft.lbs. | 1,822 ft.lbs. | 1,626 ft.lbs. | 1,449 ft.lbs. | 1,149 ft.lbs. | 917 ft.lbs. |
| Bullet Drop: | – 1.5″ | + 0.3″ | + 1.5″ | + 2.0″ | + 1.7″ | – 1.3″ | – 8.6″ |
| This is a 45-70 Ballistics chart for rifles: | |||||||
| Rifle barrel length: 24 Inches. Ammunition: Hornady 325 grain FTX bullet. Bullet diameter: .458 inch. Bullet weight: 325 grains. Bullet ballistic coefficient: .230. Rifle zero: 142 yards, 2″ mid-range rise. |
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| Range | Muzzle | 25 yds. | 50 yds. | 75 yds. | 100 yds. | 150 yds. | 200 yds. |
|---|---|---|---|---|---|---|---|
| Bullet Velocity: | 2,050 fps. | 1,966 fps. | 1,885 fps. | 1,806 fps. | 1,730 fps. | 1,585 fps. | 1,451 fps. |
| Bullet Energy: | 3,033 ft.lbs. | 2,790 ft.lbs. | 2,564 ft.lbs. | 2,354 ft.lbs. | 2,159 ft.lbs. | 1,812 ft.lbs. | 1,519 ft.lbs. |
| Bullet Drop: | – 1.5″ | + 0.2″ | + 1.4″ | + 2.0″ | + 1.9″ | – 0.6″ | – 6.5″ |
| This is a ballistics chart for the 45-70 Government rifle: | |||||||
| Rifle barrel length: 24 Inches. Ammunition: Remington 405 grain Soft Point bullet. Bullet diameter: .458 inch. Bullet weight: 405 grains. Bullet ballistic coefficient: .281. Rifle zero: 98 yards, 2″ mid-range rise. |
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| Range | Muzzle | 25 yds. | 50 yds. | 75 yds. | 100 yds. | 150 yds. | 200 yds. |
|---|---|---|---|---|---|---|---|
| Bullet Velocity: | 1,330 fps. | 1,285 fps. | 1,243 fps. | 1,204 fps. | 1,168 fps. | 1,105 fps. | 1,055 fps. |
| Bullet Energy: | 1,591 ft.lbs. | 1,484 ft.lbs. | 1,389 ft.lbs. | 1,303 ft.lbs. | 1,226 ft.lbs. | 1,099 ft.lbs. | 1,000 ft.lbs. |
| Bullet Drop: | – 1.5″ | + 0.9″ | + 2.0″ | + 1.7″ | – 0.2″ | – 8.7″ | – 24.4″ |
| 45-70 Government Reloading: |
Bullet Diameter: .458 Inch.
Maximum Case Length: 2.105 Inches.
Trimmed Case Length: 2.095 Inches.
Primer Size: Large Rifle.
Maximum Cartridge Overall Length: 2.550 Inches.
You can buy Hornady’s patented Flex Tip 325 grain 45-70 rifle cartridges at a good price by pushing that link.
.45-70 Government Black Powder —
Accuracy Test Results 1,000 Yards:
Armory at Springfield, Massachusetts, May 9, 1879. It records the results of long range tests of U.S. Army Model 1873 .45-70 Government Springfield rifles using 405 and 500 grain lead bullets, including variations in muzzle velocity and penetration of lead bullets through one-inch target boards and into sand. These tests were made at the request of the Chief of Ordnance.
Old Ordnance records show that when fired from a machine rest the .45-70 Springfield was expected to group all of its bullets inside a 4 inch circle at 100 yards, in a 11 inch circle at 300 yards, and inside a 27 inch circle at 500 yards. Though there is no direct relationship between mean radius and group size figures, the .45-70 delivered a mean radius of 18 to 19 inches which, would probably translate into a group size of between 55 and 70 inches at 1,000 yards.
Test Results 2,500 Yards:
The report of October 15, 1879, covers long range firing at Sandy Hook, New Jersey. This was done along the beach to make the location of the bullet strike easier to find. Also, the long beaches allowed shooting back to 2,500 yards.
The rifles tested included a special “long range” Springfield chambered for a 2.4 inch (.45-80) cartridge instead of the standard 2.1 inch (.45-70) cartridge. The 2.4-inch case held 80 grains of black powder behind the new prototype 500 grain lead bullet. The other load tested was the standard .45-70-405 Army load in the issue M-1873 Springfield.
Since one of the test’s objectives was to gauge bullet penetration, the huge target used consisted of three 1 inch thick boards, separated by 1 inch cleats. The target was supported on 6 inch spruce posts and was constructed partly of spruce and partly pine.
When the Springfield long range cartridge was fired, the 500-grain blunt nosed lead bullets propelled by 80 grains of black powder in the 2.4 inch cases at about 1,375 fps penetrated right through the three inches of wooden target and buried themselves in the sand. One 500 grain slug pierced three inches of target and buried itself in a supporting six inch post, giving a total penetration of a measured 5.25 inches. The Service 405-grain bullet gave a penetration of just 1.12 inches
Test Results 3,500 Yards:
The report of November 13, 1879, lists the results of firing tests made at 3,500 yards distance with two long range Springfield’s. The .45-70-500 had a rifle barrel with a l in 18 inch rifling twist, the other .45-80-500 had a l in 19 5/8 inch rifling twist. Two different loads were used: .45-70-500, and .45-80-500. The .45-70-405 Springfield’s were again tested and failed to reach the target at 3,500 yards.
Average time of flight for the .45-70-500-grain load was 21.2 seconds, the more powerful .45-80-500-grain cartridge the time-of-flight was 20.8 seconds. For 3,500 yards distance, angles of elevation ran from 27 degrees to 29 degrees.
The quicker-twist rifles required less elevation than the other slower-twist rifles at the same range. The greatest distance obtained with the .45-caliber long range, 1-in-18 twist Springfield rifle was 3,680 yards.
Since the tests showed that the 405 grain service bullet failed to perform as well as the 500 grain, and that the 500 grain bullet showed relatively little difference when propelled by either 70 or 80 grains of black powder, the .45-70-500 load in the service 2.1-inch case was adopted as standard for military rifles.
Conclusion:
1. Enlarging powder capacity from 70 grains black powder to 80 grains black powder, little gain.
2. Enlarging bullet weight from 405 grains to 500 grains, large gain in distance.
3. Faster twist rifling from 1 in 20 inch twist to 1 in 18 inch was also a long range advantage for shooting the heavier bullet of 500 grains.
The .45-70-500 load in the service 2.1 inch (.45-70) case was adopted as standard for military rifles after Sandy Hook, New Jersey tests of 1879.
.45-70 Black Powder Loads:
When reloading the .45-70 black powder cartridge, it is a good idea to start with the lowest velocity powder you can find which is Fg black powder which also gives the lowest pressure loads as well. When going with a lesser charge of black powder make sure you use a filler in the cartridge on top of powder charge so there is no air gap between bullet and powder.
.45-70 Government, Bullet Weight 405 Grains, Loaded With 50 Grains Fg Black Powder, Velocity 1,040 Feet Per Second.
.45-70 Government, Bullet Weight 405 Grains, Loaded With 60 Grains Fg Black Powder, Velocity 1,180 Feet Per Second.
.45-70 Government, Bullet Weight 405 Grains, Loaded With 70 Grains Fg Black Powder, Velocity 1,280 Feet Per Second.
.45-70 Government, Bullet Weight 500 Grains, Loaded With 50 Grains Fg Black Powder, Velocity 910 Feet Per Second.
.45-70 Government, Bullet Weight 500 Grains, Loaded With 60 Grains Fg Black Powder, Velocity 1,060 Feet Per Second.
.45-70 Government, Bullet Weight 500 Grains, Loaded With 70 Grains Fg Black Powder, Velocity 1,130 Feet Per Second.
I can’t chamber a 500 grain projectile in front of 70 grain loads, in my pedersoli rolling block.
If I have my chamber lengthend to suit this load, will I still be able to fire shorter 300 grain projectiles?