45-70 And 7×57 Mauser Compared

From Ron Spomer Outdoors

Comparing the 45-70 and 7×57 cartridges will raise eyebrows. Might even turn the air blue on some social media sites (apples to oranges!) I’ll be called everything from a dumb #$&*%! to an ignorant #+=$^@*. But we shall know the truth, and the truth shall set us free. (That’s tongue in cheek, for all you literalists.)

Seriously, why do I think it’s fair to compare the 45-70 and 7×57? Because both are used for hunting everything from whitetails and bears to moose and eland. Besides that, they have a lot in common:

1. Both were created in the latter third of the 19th century. The 45-70 Govt. in 1873, the 7x57mm Mauser in 1892.
2. Both started life as military rounds. The 45-70 in the U.S., the 7×57 Mauser in Spain.
3. Both have been used for more than a century by hunters around the world.
4. Both are still chambered in some of the most iconic, revered rifles of yesteryear and today.
5. Both have accounted for just about every terrestrial mammal species in the world.
6. Both are widely loved, hated, or ignored. Mostly ignored these days.

But the 45-70 and 7×57 also have significant differences:

1. The 45-70 Govt. throws flat-nosed, .458” diameter bullets weighing 300 to 405 grains rather slowly (2,000 to 1,300 fps MV at best.) And yes, you can handload 500-grain bullets for even more energy and penetration potential. (Read one of my accounts of 45-70 terminal performance on game here.)
2. The 7×57 propels pointed, 120- to 175-grain projectiles fairly quickly (3,000 to 2,450 fps.)
3. The 45-70 is a straight-walled cartridge.
4. The 7×57 Mauser is a bottlenecked cartridge.
5. The 45-70 was created as a black powder cartridge and, because it was chambered in rifles with weak metallurgy, is rated for a maximum average breech pressure of just 28,000 psi.
6. The 7×57 Mauser was engineered from the get go for the then new smokeless powders and chambered in strong bolt action rifles made from relatively strong steel, though not quite as strong as steel used in rifles today. It is rated for 51,000 psi. That sounds like a lot until you realize a 22-250 Remington and 7mm-08 Remington (read about it’s performance here) are rated for 61,000 psi.

45-70 Thumper And 7×57 Limping Grandma

Correct me if I’m wrong, but most hunters today think of the 45-70 Govt. as a thumper. Bear protection. Good close-cover elk cartridge. Probably knock the “moo” out of moose. The 7×57 Mauser is thought of as the 7mm Rem. Mag’s weak grandmother. Anything it can do even the little 7mm-08 Remington can do better. Why don’t we consult some ballistic data and add some facts to these suppositions? But first, a warning about factory loads:

Factory loaded 45-70 and 7×57 Mauser ammunition can be hard to find. In addition, it is usually loaded to low pressures to prevent damage in 19th century guns. The profiles of these clearly show the transition from big, blunt bullets to smaller, streamlined bullets made possible by higher energy smokeless powders at the end of the 19th century. Handloaders can improve performance of both IF they follow mainline handloading recipes and standards and shoot the rounds in strong, modern rifles.

Most, if not all, factory loadings in 45-70 ammo are held to the standard low pressures. Most common from Winchester, Remington, Federal, Barnes Vor-TX, and similar major brands are 300-grain bullets rated 1800 to 1880 fps MV. These are reportedly safe in any rifle, even 19th century Trapdoor Springfields. But many modern rifles like the 1895 Marlin I used at Fort Richmond Safaris in Africa recently, can handle much higher pressures. A few boutique ammo brands like Powder River Cartridge, Double Tap, and Buffalo Bore build loads with 405- to 500-grain bullets at slightly higher pressures (around 25,000 psi) that are supposed to safe in all guns, but I would be leery about shooting them in any rifle built prior to 1900. Handloaders can find directions and recipes for building higher pressure loads with big, heavy bullets, too. For comparison, I’ve included ballistic data for a low pressure load plus a high pressure, heavier bullet load.

Half the reason to hunt with a 45-70 is the rifle you might carry. This Marlin 1895 lever-action from the Marlin Custom Shop in Sturgis, SD, looks, handles, and functions so beautifully that it pegs the fun-o-meter even if you don’t find any game.

The 7x57mm Mauser can similarly be “fired up” by handloading to more modern pressures for use in modern rifles. By 1892 Mauser bolt actions were already a strong action, but before firing any “hot” handloads (use data from traditional handloading guides,) have a competent gunsmith examine your rifle. Any U.S. or European bolt actions built after WWI should be more than strong enough. I’ll include charts for a typical factory load and one for a top pressure load as given in Nosler Reloading Guide 8 (buy one here.)

(Zero range for all loads was established at maximum distance without putting the bullet’s mid-ordinate higher than 3 inches. Once it falls 4 inches below the aiming point, I consider it at its maximum point-blank-range.)

7×57 Mauser, 120-gr. Barnes Tsx (Handload)

7×57 Mauser, 175-gr. Nosler Ablr (Handload)

45-70 Govt., 300-gr. Barnes Tsx (Vor-tx Ammo)

45-70 Govt., 405-gr. Flat Nose Hard Cast (Double Tap Ammo)

Big Power From Small Projectile

As Gomer Pyle said back in the 1960s, surprise surprise surprise! Or maybe you already knew the 175-grain 7×57 Mauser put more punch on target at 100 yards than the celebrated 405-grain 45-70 bullet. Even the light 120-grain Barnes outmuscles the 405-grain at 150 yards. How can this be when it starts with 440 f-p less energy? Velocity plus conservation.

The narrow, pointed, streamline shape of 7×57 Mauser bullets helps them retain velocity and energy, which is why they deliver more punch beyond 150 yards than do wide, blunt bullets from the 45-70. This is why the latter is a better choice for making a big impact inside of 100 yards, the 7×57 better at longer ranges.

Muzzle velocity matters and matters a lot because doubling a moving object’s velocity quadruples its kinetic energy. Doubling its weight only doubles energy. The 7mm (.284″) bullet’s narrow, long shape and pointy nose conserve that energy by minimizing air drag. Meanwhile, the flat-nosed, wide .458 bullet wastes its energy fighting atmosphere.

Of course the small bullet benefits don’t end there. Check those drop (elevation) and drift (windage) numbers and you’ll quickly see the huge advantage the higher B.C. bullets enjoy. This is why small calibers with long, pointy bullets superseded the wide, stumpy, heavy bullets of the blackpowder era. High energy nitro powders finally gave us the velocity we needed to empower lighter, more aerodynamically efficient slugs.

Sleek, easy-handling rifles are chambered for the 7×57 Mauser, too. This Dakota Model 10 falling block is an improvement of the basic Farquharson design of 1872 and a perfect launchpad for the 7x57mm Mauser cartridge. A single 120-grain Barnes TSX applied to the shoulder of this warthog dropped him in a swirl of red dust from about 80 yards out. A Meopta Meostar R2 1.7-10x42mm, 1-inch main tube scope lit up the late evening scene beautifully.

Momentum Swings Toward 45-70 And 7×57 Loses Ground

Kinetic energy isn’t everything, of course. There is something called momentum, and that 405-grain flat-nose bears it proudly. This “trait” falls under Newton’s 1st law of motion, inertia. An object in motion tends to stay in motion. And the more mass the object has, the harder it is to stop. We’ve all experienced this when we try to shove a refrigerator across the floor. Hard to start, but once it gets moving… Put another way, would you rather catch a baseball thrown 90 miles an hour or a refrigerator sliding down a stairs? A heavy .458 bullet, especially a hard-cast lead one, expands hardly at all, but penetrates like the stare from a wounded Cape buffalo. Because it is already nearly a half-inch in diameter, fans say, expansion is not necessary.

So who wins? 45-70 or 7×57? It depends on the job at hand. Were I hoping to impress a bear or bull bearing down on me inside of 100 yards (and especially inside of 30 yards) I’d rather address it with a 45-70, the heavier the bullet the better. Were I wanting to invite an elk to dinner from more than 150 yards away, I’d send the invitation via a 175-grain AccuBond Long Range from a 7x57mm Mauser. How about you?

Back in the days of commercial ivory hunting, the diminutive 7x57mm Mauser (also known as the 275 Rigby) was employed by Karamojo Bell to take some 800 elephants. He used mostly a 173-grain, FMJ military bullet and aimed for the brain. Would you call that knockdown power?