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45-70 U.S. Government


The .45-70 cartridge was adopted by the U.S. Army in 1873. The .45-70 fired a .45 caliber 405 grain projectile over 70 grains of black powder. This provided an approximate velocity of 1,200 fps. The Army’s official designation of this new cartridge was the .45-70-405. The caliber was .458” (11.6mm) and the rifling consisted of 1 turn in 20”. The rifle of the period that utilize this new round was the M1873 Springfield rifle known as the Trap Door. The military demanded accuracy out of a rifle to hold a four shot group at 100 yards to a maximum of 4”. The Army considered the rifle & round effective to about 300 yards however also used it for volley fire out to 600 yards. The .45-70-500 (500 grain bullet) was later developed and found to be more efficient from a ballistic stand point.

The .45-70 was phased out as a Military cartridge after the Spanish American war due to enemy forces having repeating rifles. As a hunting cartridge the 45-70 was very well received. The commercial designation of the cartridge was .45 Government later known as the .45-70 U.S. Government. Even more recently abbreviated as either the .45-70 Government or just the .45-70 Govt.

For decades the .45-70 has been appreciated for its power and capability of taking all North American game in a reliable manor. During the period of the 1880’s through the 90’s the .45-70 was the most popular big game cartridge in the United States. As with every generation, desire for faster shooting, lighter rifle calibers slowed the popularity of the .45-70 to a point where no rifles were being built in the caliber after the 1930’s. As time went on, the hunting community using the old .45-70 cartridge in black powder almost phased out.

The Marlin Firearms Company introduced their new model 1895 lever action rifle in .45-70 in 1972. This of course utilized a smokeless powder version of the cartridge in a repeating rifle. This brought the .45-70 Govt. back into a very favorable position and it has since become a favorite again of big game hunters in the United States, Australia & New Zealand.


If you’ve been around the .45-70 for any period of time you recognize that generally speaking there are three categories of rifles that fire the cartridge. It really comes down to the strength of the rifle action. The Trap Door Springfield and early lever action rifles are known to be the weakest. Modern replicas are also included in this category. For this very reason, most modern factory ammunition is loaded at low pressures suitable for use any .45-70 rifle. Maximum pressures are usually mentioned as 28,000 CUP or 28,000 PSI (similar correlation). A typical factory load for a Trap Door within this pressure is made up of a 300 grain bullet with a muzzle velocity of 1,800 fps out of a 24” barrel.

The next level of performance in the .45-70 cartridge comes with the use of high pressure loads in post 1972 Marlin 1895 rifles. Reloading documentation across the industry suggest maximum pressures of 40,000 CUP or 45,000 PSI. The modern Marlin rifle has proven to be a very strong action with the 444 Marlin cartridge being loaded up to 47,000 PSI. A typical hand loaded cartridge for the .45-70 high pressure rifles consists of a 300 grain bullet driven at 2,400 fps from a 24” barrel.

The third level of performance for the .45-70 cartridge with the highest pressures are used expressly in Ruger No. 1 single shot rifles as well as various custom built bolt action rifles. Reloading guides suggest maximum pressures of 50,000 CUP or 60,000 PSI. A typical load consists of a 300 grain bullet at 2,500 fps.

Factory ammunition

As mentioned previously, all United States ammunition produced by major manufacturers is loaded to very safe pressures for use in antique arms. All of the big name manufacturers produce 300 grain jacket hollow point rounds delivering between 1,650 fps & 1,750 fps in 22” to 24” barrels. In the 18-1/2” barreled popular Marlin Guide Guns the velocity for same is approximately 1,600 fps. All of these similar loads are meant for medium sized game and over time have proven to be very dependable in the field.

There are so many bullet types & weights available for the hand loader that the .45-70 is suitable for pests to pachyderms and everything in between.

Final thoughts

The .45-70 is my favorite big bore lever action cartridge by far. I prefer the shorter barreled Guide Gun configuration for pushing through tight brush however I’m just as comfortable with a longer barreled version. The hand loader (as with many lever gun cartridges) has many options for loading over available factory ammunition. The .45-70 is proven capable of even taking the Big 6 African dangerous game. Having a .45-70 lever gun on your shoulder walking through bear territory brings a sense of security although caution should still be observed.

45-70 SAAMI Data


45-70 Solid Brass 325 grain


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