The .45 Auto Rim is a pistol cartridge with an extra thick rim that allows it to be used without a moon clip in revolvers designed for a .45 Auto moon clip combination.
The 45 Auto Rim is not listed in SAAMI’s rifle (Z299.4), handgun (Z299.3) or rimfire (Z299.1) standards, so there is no SAAMI reference velocity, pressure limit or test barrel to quote for it. This guide charts what the makers of the loads we stock publish for them instead, and compares the 45 Auto Rim with the 45 Automatic, which SAAMI does standardise.
45 Auto Rim ballistics chart: manufacturer-published loads
These are the manufacturers’ own figures for specific loads we stock, taken from each maker’s page for the item number shown. There is no SAAMI reference for this cartridge, and each maker chose its own test barrel, so the figures should not be laid directly beside another brand’s.
Scroll the table sideways for the remaining columns.
| Load | Item no. | Bullet weight | Bullet | Muzzle velocity | Muzzle energy | Test barrel |
|---|---|---|---|---|---|---|
| Buffalo Bore Jacketed Hollow Point | 32B | 200 gr | Jacketed Hollow Point | 1,200 fps | 639 ft-lb | Not published |
| Buffalo Bore Hard Cast Wadcutter | 31C | 225 gr | Hard Cast Wadcutter | 950 fps | Not published | Not published |
| DoubleTap Ammunition Controlled Expansion™ JHP | Not published | 230 gr | Controlled Expansion™ JHP | 900 fps | 415 ft-lb | 6.0″ bbl. S&W 625 |
| Buffalo Bore H.C. F.N. | 32A | 255 gr | H.C. F.N. | 1,000 fps | 566 ft-lb | Not published |
| DoubleTap Ammunition Keith Style SWC Hard Cast | Not published | 255 gr | Keith Style SWC Hard Cast | 900 fps | 463 ft-lb | 6.0″ bbl. S&W 625 |
What the numbers mean for a shot
The 5 loads charted above, from Buffalo Bore and DoubleTap Ammunition, run from 200 to 255 grains, with published muzzle velocities of 900 to 1,200 fps and published muzzle energies of 415 to 639 ft-lb. Each maker fired its load in its own test barrel, so a difference between two brands can come from the barrel as well as the load.
None of this is SAAMI data. Each product in our 45 Auto Rim ammo range lists whatever its maker publishes for that item.
Chamber and pressure
This page states no SAAMI pressure limit for the 45 Auto Rim. Fire 45 Auto Rim ammunition only in a firearm chambered for it, and follow both the ammunition maker’s and the firearm maker’s instructions. Several unrelated cartridges share a number, so match the full designation on the box to the marking on your barrel.
45 Auto Rim vs 45 ACP: what the data supports
A like-for-like comparison needs both cartridges measured the same way. SAAMI standardises the 45 Automatic, so its figures come from one standard test barrel. The 45 Auto Rim has no SAAMI figures, so its numbers come from individual makers and their own barrels. The table sets them side by side with the source of each figure stated, and should be read that way.
Scroll the table sideways for the remaining columns.
| Specification | 45 Auto Rim | 45 Automatic |
|---|---|---|
| Listed by SAAMI | No | Yes |
| Maximum average pressure | Not published by SAAMI | 21,000 psi (SAAMI) |
| Bullet weights | 200 to 255 gr (loads we stock) | 120 to 230 gr (SAAMI reference loads) |
| Muzzle velocity | 900–1,200 fps (manufacturer-published, each in its own barrel) | 770–1,200 fps (SAAMI reference, 5.000 in test barrel) |
| Muzzle energy | 415–639 ft-lb (where the maker publishes it) | 244–497 ft-lb (computed from SAAMI velocity) |
What this cannot settle is which cartridge is more powerful in your rifle: the two columns come from different sources and different barrels. We stock the other side of this comparison too: 45 ACP ammo.
45 Auto Rim ballistics questions
Does SAAMI standardise the 45 Auto Rim?
No. SAAMI’s rifle, handgun and rimfire standards do not list the 45 Auto Rim, so there is no SAAMI maximum pressure, reference velocity or test barrel for it. The figures on this page are the ones each maker publishes for its own loads.
What muzzle velocity do manufacturers publish for the 45 Auto Rim?
For the 5 loads we stock from Buffalo Bore and DoubleTap Ammunition, the makers publish muzzle velocities from 900 to 1,200 fps, for bullet weights from 200 to 255 grains. Each maker measured its own load in its own test barrel, so these are not reference figures and are not directly comparable between brands.
Is the 45 Auto Rim more powerful than the 45 Automatic?
The two cannot be compared like for like, because SAAMI publishes reference data for the 45 Automatic but not for the 45 Auto Rim. The 5 loads charted here for the 45 Auto Rim publish muzzle energies of 415 to 639 ft-lb, each in its maker’s own barrel, against SAAMI reference loads for the 45 Automatic that compute to 244 to 497 ft-lb from a 5.000 in test barrel.
What is the effective range of the 45 Auto Rim?
Effective range is not a published specification for the cartridge; it depends on the bullet, the load and the shooter. Where a maker publishes downrange velocity and energy for a load, the tables above show it, and only out to the last range that maker publishes.
How much does the 45 Auto Rim drop?
None of the makers of the loads we stock publishes a trajectory table for them, so this page gives no drop figure. Drop depends on the bullet’s ballistic coefficient and on the zero range, so use the figure a maker prints for the specific load.
Where to buy these loads
Hilltop Armory carries 45 Auto Rim ammunition from Buffalo Bore, CorBon, DoubleTap Ammunition and Black Hills Ammunition. Browse the full 45 Auto Rim ammo range.
