With the popularity of the AR-15 platform, and the growing popularity of the AR-10/AR-308 platform, numerous gunsmiths, wildcatters, and tinkerers have developed new cartridges in an attempt to adapt these popular platforms for different purposes. Among the cartridges developed are big bore cartridges that seek to maximize the power possible from these platforms. And one of those whose popularity seems to be sticking around is the .45 RAPTOR.
The .45 RAPTOR is an attempt to create a powerful big bore hunting cartridge for the AR-308 (DPMS-compatible) platform. The cartridge is the brainchild of Arne Brennan, who was involved in the early development of the 6.5 Grendel cartridge, and who has developed other RAPTOR family cartridges including the .375 RAPTOR.
The .45 RAPTOR attempts to mimic the performance of the .460 S&W Magnum but in a semiautomatic rifle. The case is developed from the .308 Winchester, but is more or less a rimless version of the .460 S&W. Thus, all load data from the .460 S&W can be used to load the .45 RAPTOR.
Because of its longer barrel, the .45 RAPTOR is therefore able to provide superior ballistic performance to the .460 S&W. The .45 RAPTOR can push 200-grain bullets to up to 2,850 feet per second, and 300-grain bullets to 2,300 feet per second from a 16-inch barrel, for around 3,500 foot-pounds of muzzle energy. That’s significantly more energy than the .308 Winchester, more even than cartridges like the .30-06 Springfield, and is more than enough to take any large game in America.
The .45 RAPTOR can use any bullets intended for use in the .460 S&W or the .454 Casull, and can fit bullets up to 400 grains in weight. Published load data shows that the .460 S&W Magnum should be able to push a 395-grain hardcast lead bullet to 1,800 feet per second out of a 10.7” barrel. That would indicate that the .45 RAPTOR should be able to push that same bullet to 1,900 to 1,950 feet per second, for 3,400 foot-pounds of muzzle energy. In essence, the .45 RAPTOR is like a semiautomatic version of modern high-powered .45-70 loads.
The downsides to the .45 RAPTOR, unfortunately, are numerous. First, the cartridge requires a special barrel extension and a specially modified magazine. Standard straight (non-curved) DPMS-compatible magazines need a special magazine block inserted into the front that acts in concert with the barrel extension to provide a feed ramp. This means that you can forget about using off the shelf AR-308 magazines, or any with a curve such as Magpul magazines. However, you retain full magazine capacity with these modified magazines.
The other downsides include the cost and availability of components. There is currently little ammunition in stock, and you’re largely at the mercy of two manufacturers, Underwood and Buffalo Bore. Expect to pay between $2.50 and $4 per round for factory ammunition.
Reloading components are also pricey, with brass running 60 to 80 cents per piece and often out of stock. Bullets are getting more expensive too, so expect to pay a minimum of about 40 to 50 cents per bullet. Thankfully the .45 RAPTOR can be sized with .460 S&W or .454 Casull dies, along with a .308 Winchester shellholder. But feeding your .45 RAPTOR isn’t going to be easy.
If you live in an area where having a semiautomatic .45-70 is almost a requirement, like Alaska or the hinterlands of the American West, then the .45 RAPTOR in an AR-308 platform may be a good choice for you. But in order for it to be a viable survival cartridge for you, you’ll have to stock up on magazines, ammo, and reloading components if you want to keep it running when you need it most.