The 45-70 Government is a historic straight wall cartridge that remains incredibly popular for big game hunting. This article contains published 45-70 reloading data categorized strictly by firearm action strength to help you find a safe powder charge. Keep in mind that exact data depends heavily on your specific rifle action, bullet weight, components, and the original publishing source.
45-70 Reloading Data
| Cartridge Action | Bullet Weight (Grs.) | Powder | Min Charge (gr) | Max Charge (gr) | Max Velocity (fps) |
| Trapdoor (Weak) | 300 | IMR 4198 | 29.0 | 32.5 | 1,500 |
| Trapdoor (Weak) | 405 (Cast) | Trail Boss | 12.0 | 13.0 | 1,000 |
| Trapdoor (Weak) | 405 | IMR 3031 | 34.0 | 38.5 | 1,350 |
| Lever Action (Strong) | 300 | IMR 4198 | 40.0 | 44.5 | 1,900 |
| Lever Action (Strong) | 300 | H322 | 55.0 | 60.0 | 2,150 |
| Lever Action (Strong) | 350 | IMR 3031 | 51.0 | 56.5 | 1,950 |
| Lever Action (Strong) | 400 | IMR 4198 | 35.0 | 39.0 | 1,650 |
| Modern (Very Strong) | 300 | IMR 4198 | 44.0 | 47.5 | 2,000 |
| Modern (Very Strong) | 400 | H322 | 50.0 | 55.0 | 1,900 |
Explanation Of The Data
The supplied 45-70 reloading data covers the three distinct power levels required for safely loading this historic cartridge. Because firearms chambered in 45-70 vary drastically in age and design strength, publishers of reloading manuals separate load data into three distinct chamber pressure categories.
Trapdoor Actions
Loads designed for original 1873 Springfield Trapdoor rifles and early Remington Rolling Blocks are kept to mild pressures. For a traditional 405 grain cast bullet, a fast burning powder like Trail Boss requires only 12.0 to 13.0 grains to safely reach roughly 1,000 fps. Using a lighter 300 grain jacketed bullet with IMR 4198 restricts the maximum charge to 32.5 grains, capping velocity at 1,500 fps to ensure chamber pressure remains safe for antique firearms.
Lever Actions
Modern Marlin 1895 and Winchester 1886 lever action rifles can handle significantly higher pressures than antique Trapdoors. For a 300 grain bullet, a powder like H322 can be pushed from a starting load of 55.0 grains up to a maximum of 60.0 grains, yielding speeds near 2,150 fps. Heavier 350 grain or 400 grain bullets demand reduced powder charges, such as 35.0 to 39.0 grains of IMR 4198, to maintain safe pressure ceilings while still delivering immense downrange energy.
Modern Actions
Rifles like the Ruger No. 1 falling block are considered modern actions and can handle the absolute highest 45-70 pressures. In these robust single shot rifles, a 300 grain bullet can safely utilize up to 47.5 grains of IMR 4198. Heavy 400 grain bullets can be loaded with up to 55.0 grains of H322, creating massive recoil and terminal performance that rivals modern magnum cartridges.
Understanding 45-70 Load Data
A starting load is the lowest recommended powder charge to safely fire the bullet without causing pressure anomalies. The maximum published load represents the highest safe charge before exceeding established pressure limits for that specific action class. Velocity is the muzzle speed measured in feet per second (fps). Bullet weight and barrel length significantly impact these numbers. Heavier bullets demand smaller powder charges, while longer barrels generally increase velocity. Cartridge overall length is critical in lever actions to ensure proper feeding from the tubular magazine and to prevent bullets from being pushed deeply into the case during recoil.
Manufacturer Data vs Provided Data
The provided table is built on authoritative published data from sources like the Hodgdon Reloading Data Center and classic Lyman manuals. The data correctly categorizes loads by action strength, a strict standard practice across the reloading industry for the 45-70 cartridge. Minor variations will occur if you cross reference this chart with other sources due to different test barrels, brass case wall thicknesses, and primer types. Always verify your chosen load against current manufacturer load data.
45-70 Safety
Reloading data is component specific. You must clearly identify the strength of your rifle action before selecting a powder charge. Firing a Lever Action or Modern load in a Trapdoor rifle can cause catastrophic firearm failure and severe injury. Never substitute bullet brands, primers, or brass without consulting published data, as doing so can dangerously spike chamber pressure. Starting and maximum loads must not be confused. Always follow published manufacturer data exactly as printed.
FAQs
What is 45-70 reloading data?
It is the tested and published specifications for handloading the 45-70 Government cartridge, detailing safe powder charges for various bullet weights and rifle action types.
Why is 45-70 load data split into three categories?
The data is separated into Trapdoor, Lever Action, and Modern categories because antique rifles cannot withstand the high chamber pressures generated by loads intended for modern, stronger firearms.
What powders work best for the 45-70?
Popular powders for the 45-70 include IMR 4198, H322, IMR 3031, and Trail Boss for light cast bullet loads.
What bullet weights are common in 45-70 reload data?
Common bullet weights range from light 300 grain jacketed hollow points up to traditional 405 grain and 500 grain cast lead bullets.
Can I use Modern 45-70 loads in a lever action rifle?
No, loads specifically designated for Modern actions like the Ruger No. 1 exceed the safe pressure limits of tubular lever action rifles.
Where can I find a 45-70 load data chart?
You can find comprehensive 45-70 load data charts in printed reloading manuals from bullet manufacturers or online at the Hodgdon Reloading Data Center.
Does Hodgdon publish 45-70 reloading data?
Yes, Hodgdon publishes extensive data for the 45-70, carefully categorized by the three distinct rifle action strength levels.
How does bullet seating depth affect 45-70 pressure?
Seating a bullet too deeply reduces the internal case capacity, which can cause dangerous spikes in chamber pressure, especially with heavy maximum loads.