Buffalo Bore Ammunition 45 Auto Rim (Not ACP) 255 Grain Hard Cast Lead Flat Nose 20RD

Buffalo Bore Ammunition's 45 Auto Rim load brings serious stopping power to revolvers and lever-action rifles that chamber this distinctive cartridge. Built with a 255-grain hard cast lead flat nose bullet, this ammunition delivers the penetration and expansion characteristics that have made Buffalo Bore a favorite among hunters and shooters who refuse to compromise on performance. The 45 Auto Rim is decidedly different from 45 ACP—it headspaces on the case rim rather than the case mouth, which means it's purpose-built for revolvers like the Colt M1917 and modern reproductions, plus certain lever guns. If you've got one of these firearms, Buffalo Bore's load respects that platform with ammunition specifically designed for it.

Hard cast lead bullets are engineered to resist deformation and fragmentation, making them ideal for deep penetration on larger game or when barrier performance matters. The flat nose profile contributes to a wider wound channel and reliable expansion. This is the kind of ammunition that performs the job hunters expect—no flash, no drama, just consistent terminal ballistics when it counts. Standard pressure means you get reliable ignition and cycling without unnecessary wear on your gun.

Buffalo Bore packages this load in 20-round boxes, so you can stock up for hunting season, practice, or keep reliable ammunition on hand for your revolver. As with any ammunition, verify chamber compatibility and headspace before firing—especially important with 45 Auto Rim, since confusing it with 45 ACP can cause real problems.

Key Features

• 255-grain hard cast lead bullet for deep penetration and reliable performance
• Flat nose profile for wider wound channel and consistent expansion
• Headspaces on the case rim—designed for 45 Auto Rim revolvers and lever-action rifles, not 45 ACP
• Standard pressure load for reliable cycling and reduced firearm wear
• 20 rounds per box for convenient carry and use

Specifications

Frequently Asked Questions

Is this 45 Auto Rim ammo compatible with 45 ACP guns?

No. 45 Auto Rim and 45 ACP are different cartridges with different headspacing systems. 45 Auto Rim headspaces on the case rim and is designed for revolvers and some lever-action rifles. 45 ACP headspaces on the case mouth and is used in semi-automatic pistols. Never attempt to fire 45 Auto Rim in a 45 ACP chamber, or vice versa. Always verify your firearm's chamber marking before selecting ammunition.

What revolvers use 45 Auto Rim ammunition?

The Colt M1917 and other service revolvers of that era chamber 45 Auto Rim, as do modern reproductions and some specialized revolvers. Verify the headstamp or markings on your revolver to confirm it's chambered for 45 Auto Rim before purchasing ammunition.

Why choose hard cast lead bullets?

Hard cast lead bullets resist deformation and fragmentation, delivering superior penetration compared to softer bullets. They're particularly effective on larger game and in situations where barrier performance or deep, consistent penetration is required. The flat nose profile of this load adds to wound channel width.

How much ammo comes in a box?

Each box contains 20 rounds, allowing you to stock up for hunting or practice without excessive packaging waste.