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.45-70 Black Powder Cartridge Long Range Tests:
Written by: Kim Lockhart, Copyright.
.45-70 Government, 1873 Springfield Rifle
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 Springfields. 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 Springfields 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.
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.
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