Brass Fetcher Ballistic Testing
Before small, high velocity rifle bullets were popular, there was the 45-70 Government. This excellent cartridge is still popular today for hunting at moderate ranges and can certainly be used for self-defense. Propelling a 300gr bullet at 1850 ft/sec, the 45-70 Government cartridge is more like a high-performance 20 gauge shotgun slug than it is like a conventional rifle.
Let’s take a look below at the downrange performance of this cartridge (see Figure 1):
The rock-like trajectory of the 45-70 Government versus more streamlined rifle cartridges becomes apparent from the chart (see Figure 1). Fortunately, the trajectory still allows the rifle to be used for emergency shots at ranges beyond 200 yards but beyond this distance, the drop will be difficult to compensate for without the use of a drop-compensating reticle. With a scope that offers 1/4 inch adjustment, it would require 600 clicks in order to dope your scope to compensate for bullet drop at 500 yards. This is beyond the range of adjustment for most commercial scopes. Even with more streamlined bullets like the Hornady LEVERevolution, it would require a lot of guesswork to successfully hold over with a 45-70 Government rifle beyond 200 yards distance.
Regarding terminal ballistics, the 45-70 Government cartridge excels in the 50 yard fight. It is interesting to note that hand-thrown weapons such as grenades and Molotov cocktails are not effective beyond 50 yards and shotguns and pistols are marginally effective at this distance. How good would it be to have a rifle that can inflict devastating wounds at this range and is still capable of deterring an attack to 200 yards? Expanding bullets have the problem of structural integrity as velocity increases and as the expansion increases. The reason is that expanding bullets require considerable fluid pressure in order to expand. This same fluid pressure acts on the extreme ends of the expanded bullet, which acts as a fulcrum to tear the expanded ‘petal’ away from the bullet core.
Bullets which start out with a larger diameter need to expand less in order to present the same surface area than do smaller diameter expanding bullets. In this way, larger diameter expanding bullets offer more bullet integrity than smaller expanding bullets. What I would like to see is a full-on 45-70 Government load that expands to a large diameter and penetrates to 12.0” inches in 10% ballistic gelatin. To date, the shallowest penetration depth that I have observed in ballistic gelatin is in the neighborhood of 16”. The more the bullet ‘throws on the brakes’, the more damage it will do but the lower the penetration will be.
An interesting load for this cartridge is a multi-ball load developed by Frankford Arsenal in 1901. Going from the cut-away photograph below, we see three spheres, likely 0.458” diameter lead spheres. The chamber pressure is increased when projectiles are seated deeper into the cartridge case. Without specialized (expensive) propellant, you will need to decrease the propellant charge in order to keep the chamber pressure down to safe levels. This also reduces the chemical potential energy stored in the propellant, which will decrease the velocity of each projectile as it emerges from the muzzle of the weapon..
What I do like about the multi-ball load is the ability to increase your hit probability substantially. Although this comes at the expense of the lethality of each individual shot pellet being much lower than the single projectile load, the increase in hit probability could pay high dividends if shooting at night or in foul weather where visibility of the target (and your sights) are limited. With a gun as stout as a 45-70 Government in terms of recoil, I cannot imagine getting more than one shot at a running target. Why miss with a single projectile when you might be able to score a hit or two with the multi-ball load?
Ammunition selection for the 45-70 Government is simple—you can choose from expanding bullets with moderate recoil or hard cast/limited expansion bullets that will let you know that you pulled the trigger. For general use, I recommend the 300gr expanding bullet loaded as hot as you can tolerate (and traveling as fast as the bullet will hold together for.) If you are lucky enough to live in a place with Brown bears or other large animals that you might consider to be a potential threat, then I strongly recommend the hardest non-expanding bullets that you can control in your rifle.
Please be aware that there are three ’strengths’ of 45-70 Government cartridge available: the load appropriate for the Trapdoor Springfield, ’lever action loads’ and ’Strong Action only loads’. This is not prose or warning for the sake of sounding important. I intentionally shot a ’lever action load’ in a derringer which is designed for the Trapdoor loads only. The first shot (fired with the guns grip clamped in a vise) seemed to go ok. The second shot made the action a little bit hard to open. After reloading the weapon, the third shot stretched the frame and broke the firearm. You read that right—the firing pressure of the cartridge exceeded the ultimate tensile strength of the steel that the derringer was made of.
The recoil of the 45-70 Government and the close-range dominance of the weapon is an interesting topic that I hope is worth your consideration. On the one hand, firearms that are quick-handling are considered to be particularly useful for close-range shooting. This is backed up by the terminal ballistics of this cartridge being excellent while the velocity is still high. On the other hand, quick-handling firearms are made less ‘quick’ by the inclusion of rubber butt pads. Rubber butt pads will usually snag on your shirt as you are shouldering the weapon. The two techniques I know that fix that is to apply duct tape to the sides of the butt pad or to push the weapon a few inches towards the target as you bring it up (and then pull it back into your shoulder) or to simply man-up and eat the recoil of a steel or hard plastic buttplate. It also requires practice to be able to take that sort of beating—if you don’t place such a buttstock in the ‘pocket’ of your arm, the perceived recoil will be considerably worse than if you had.
10-percent Ballistic Gelatin Shots
See how well this caliber stacks up against the FBI performance requirement of expansion and 12.0” or deeper penetration depth.
20-percent Ballistic Gelatin Shots
See how well this caliber stacks up in military-standard performance evaluations.
FBI Standard test simulating a shot through a car windshield.