Head to head

45-70 Government vs .450 Bushmaster: Maker-Page Loads and SAAMI Specs Side by Side

By Cole Harlan, EditorUpdated Nov 5, 2026How we verifyEditorial standards

This page puts 45-70 Government and .450 Bushmaster side by side using only our own ammo guides, 45-70 Government ammo (15 loads) and .450 Bushmaster ammo (10 loads), plus the cartridge specs SAAMI publishes in ANSI/SAAMI Z299.4, its centerfire rifle standard. The guides copy bullet weights, velocities, energies and test barrels from maker product pages (the 45-70 loads checked Nov. 5, 2026 and the .450 Bushmaster loads Nov. 4, 2026). We don’t rate or rank cartridges, and we don’t subtract one maker’s velocity from another’s, because their test barrels differ.

How to read this page: every number is copied from a maker page or from SAAMI, and a test barrel length sits next to every velocity (or says the maker lists none). A dash (—) means the maker has no load in our tables for that cartridge. Fire only the cartridge your rifle’s maker says it is chambered for.

SAAMI specs side by side

These are the figures in ANSI/SAAMI Z299.4 (approved Feb. 10, 2025), as already recorded in the SAAMI sections of our 45-70 Government and .450 Bushmaster guides. Pressures are as SAAMI lists them.

Measure	45-70 Government	.450 Bushmaster
SAAMI name	45-70 GOVERNMENT [45-70 GOVT]	450 BUSHMASTER [450 BM]
Drawing issued / revised	05/29/1979 / 02/10/2023	02/01/2008 / 08/23/2022
Maximum average pressure (transducer)	28,000 psi	38,500 psi
Crusher pressure	28,000 CUP	Not established
Cartridge overall length	2.490 in min to 2.550 in max	2.000 in min to 2.260 in max
Case length	2.105 in (−.020)	1.700 in (−.010)
Bullet diameter (as SAAMI prints it)	.458 in (−.003)	.4525 in (−.0030)
Bore / groove diameter	.450 in / .456 in	.442 in / .450 in
Twist and grooves	1 in 20, 6 grooves	1 in 24, 6 grooves
SAAMI reference velocity	Not yet verified (the PDF text does not clearly pair each weight with its velocity)	Not yet verified (the PDF text does not clearly pair each weight with its velocity)
SAAMI velocity test barrel	24 in standard rifle test barrel (SAAMI’s general statement; not among its listed exceptions)	24 in standard rifle test barrel (SAAMI’s general statement; not among its listed exceptions)

SAAMI’s calibration table (Section II) carries a footnote on the 45-70 Government: “The calibration band for the 45-70 Gov’t does not conform to the standardized guidance due to testing done on ammunition loaded to 18,000 psi.” We copy the maximum average pressure as SAAMI lists it and add nothing to it. See also our SAAMI maximum average pressure table.

Load ranges by maker and test barrel

Each line groups one maker’s loads that share a test barrel, so a velocity is only ever shown with the barrel it was measured in. Ranges are bullet weight and muzzle velocity as the maker page prints them. Do not read across makers: their barrels and bullets differ. For how barrel length moves velocity, see our barrel length vs velocity data.

Maker	45-70 Government loads in our table	.450 Bushmaster loads in our table
Federal	test barrel not listed: 7 loads, bullet weight not printed in our table, 1,000 to 1,850 fps	test barrel not listed: 3 loads, 260 to 300 gr, 1,900 to 2,200 fps
Remington	test barrel not listed: 5 loads, bullet weight not printed in our table, 1,000 to 2,100 fps	test barrel not listed: 3 loads, 260 gr, 2,040 to 2,180 fps
Hornady	24 in test barrel: 3 loads, 250 to 410 gr, 1,075 to 2,025 fps	20 in test barrel: 4 loads, 245 to 395 gr, 1,050 to 2,200 fps

Same maker, same line, both cartridges

Where one maker sells the same product line in both cartridges, the loads are listed side by side exactly as the maker pages print them. We match lines by the maker’s own product-line name in our guide tables. Compare only within a row, and check the test barrel in each cell.

Maker line	45-70 Government	.450 Bushmaster
Federal Fusion Rifle	Fusion Soft Point, 1,850 fps, 2,280 ft-lb, test barrel not listed, item F4570FS1	260 gr Fusion Soft Point, 2,200 fps, 2,794 ft-lb, test barrel not listed, item F450BMFS1
Federal Power-Shok Rifle	Jacketed Soft Point, 1,850 fps, 2,280 ft-lb, test barrel not listed, item 4570AS	300 gr Soft Point, 1,900 fps, 2,405 ft-lb, test barrel not listed, item 450BMB
Remington Core-Lokt	Core-Lokt Soft Point, 1,330 fps, 1,591 ft-lb, test barrel not listed, item 29473 Core-Lokt Soft Point, 1,600 fps, 2,302 ft-lb, test barrel not listed, item 21459	260 gr Pointed Soft Point Core Lokt, 2,040 fps, 2,402 ft-lb, test barrel not listed, item 27941

What the sources say when you choose

These are points taken from the figures above, each with the page it rests on. They are not recommendations or scores.

If pressure rating is your question: SAAMI lists a maximum average pressure of 28,000 psi by transducer (plus 28,000 CUP by crusher) for 45-70 Government and 38,500 psi by transducer for .450 Bushmaster, with no crusher pressure established where none is shown. Source: ANSI/SAAMI Z299.4.
If bullet weight is your question: the 45-70 Government loads in our table run from 250 gr (Hornady LEVERevolution 82741) to 410 gr (Hornady Sub-X 82742). The .450 Bushmaster loads run from 245 gr (Hornady American Whitetail 82242) to 395 gr (Hornady Sub-X Subsonic 82247). Sources: those maker pages.
If you want to see the printed velocities: the slowest and fastest 45-70 Government muzzle velocities in our table are 1,000 fps, test barrel not listed (Federal Subsonic F4570FS1SUB) and 2,100 fps, test barrel not listed (Remington Core-Lokt Tipped Lever Gun R21430). For .450 Bushmaster they are 1,050 fps, 20 in test barrel (Hornady Sub-X Subsonic 82247) and 2,200 fps, test barrel not listed (Federal Fusion Rifle F450BMFS1). These come from different barrels and bullets, so we show them side by side without subtracting.
If you are comparing against a box or a chronograph: SAAMI says all standard rifle test barrels are 24 in long, and neither cartridge is on its list of exceptions. Many maker pages list a different barrel or none, as the tables above show. A shorter barrel than the one a maker lists will likely give lower velocities than the box; see our barrel length vs velocity data. Source: ANSI/SAAMI Z299.4 and the maker pages linked above.
If chamber fit is your question: SAAMI publishes a separate cartridge drawing for each, with case length 2.105 in (−.020) for 45-70 Government and 1.700 in (−.010) for .450 Bushmaster, and cartridge overall length 2.490 in min to 2.550 in max and 2.000 in min to 2.260 in max. Check the cartridge named in your rifle’s manual or marked on its barrel. Source: ANSI/SAAMI Z299.4.

Not yet verified

SAAMI reference velocities are not recorded for either cartridge in our guides because the PDF text does not clearly pair each weight with its velocity.
45-70 loads from other makers, and loads built for older rifles, may differ from the three makers in our table; read the maker’s own page for your rifle.
A dash in the range table means the maker has no load in that guide’s table, not that the maker sells none.
Prices, recoil, accuracy and hands-on results are not in our data, so this page says nothing about them.

See the full tables in our 45-70 Government ammo and .450 Bushmaster ammo, the barrel length vs velocity data, .350 Legend vs .450 Bushmaster, the new ammo of 2026, all ammo releases and all comparisons.

Frequently asked questions

What is the SAAMI maximum pressure for 45-70 Government and .450 Bushmaster?

SAAMI lists 28,000 psi (transducer) and 28,000 CUP (crusher) for 45-70 Government, and 38,500 psi (transducer) for .450 Bushmaster, in ANSI/SAAMI Z299.4.

Which test barrel do the makers list?

It varies by maker and load. SAAMI says standard rifle test barrels are 24 in. Our tables show the barrel each maker page lists next to every velocity, and many pages list none.

Which is better, 45-70 Government or .450 Bushmaster?

We don't rate or rank cartridges. This page copies maker-page figures and SAAMI specs side by side, and it does not cover price, recoil or hands-on results.

Where do these numbers come from?

From our own ammo guides (45-70 Government ammo and .450 Bushmaster ammo), which copy maker product pages, and from ANSI/SAAMI Z299.4.

SAAMI specs side by side

Load ranges by maker and test barrel

Same maker, same line, both cartridges

What the sources say when you choose

Not yet verified

Related guides

Frequently asked questions

Sources

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