Remember your excitement when you got your first AR-15? If you’re like me, it was memorable! Now imagine something even more so – getting something BIGGER!  Yes, it’s just a matter of time before you’ll get the itch to join the “BIG BORE” club. Typically characterized by calibers .44 greater, big bore ARs are a ton of fun to shoot, usually better for hunting and good for the ego!  One of these “BIG BORE” bad boys is the 450 Bushmaster, a formidable beast with the ability to provide a one-shot kill at 250 yards. Feel the itch yet? I did, and that .450 Bushmaster became my first entry into the Big Bore Club.

.450 Bushmaster History

The 450 Bushmaster DNA goes back to the legendary Col. Jeff Cooper and his disdain for the .223 caliber AR-15 platform. Cooper was convinced of the need to go bigger. He envisioned a cartridge for big game hunting out to 250 yards.  That idea inspired Tim LeGendre of LeMag Firearms, LLC to develop the “.45 Professional Cartridge” which would utilize .452 projectiles.

Later, LeGendre licensed the .45 Professional to Bushmaster Firearms International. Bushmaster teamed up with Hornady Ammunition to produce it. Hornady wanted to modify the original concept to incorporate its 250 grain Super Shock Tip (SST) bullet.  This forced a compromise to shorten the cartridge case and the Bushmaster 450 was born.

Hornady .450 Bushmaster Ammo

I’ve used Hornady ammo for years in most of my traditional hunting rifles, so the decision for me was simple.  The .452” 250 grain FTX features Hornady’s Flex Tip technology is a solid choice.  It provides great velocity and devastating energy out to 300 yards. It has a ballistic coefficient .210 and 2200 feet per second muzzle velocity. These FTX bullets (this one is built for the .45 Colt) are designed to have a much higher BC than normal flat-nosed bullets standard in those types of cartridges. The FTX bullets are somewhat soft and offer very good expansion, but are not the best bullets for the toughest game. In North America they are suitable for anything but brown or polar bears, and perhaps bison.

Zeroed at around 175 yards, this load is easily a 200 yard load without worrying much about hold overs.

Remington .450 Bushmaster Ammo

Remington also jumped into the mix and now provides several options for the .450 Bushmaster. For reloading, the 275 grain Barnes XPB has a .215 ballistic coefficient. Designed for the increased muzzle velocity and long barrels available on .460 S&W hunting pistols, this Barnes solid projectile is a game-changer for the .450 Bushmaster. This is the load I would choose if I were using the .450 BM in bear country. Trajectory is basically identical to the Hornady 250 grain FTX load at practical ranges, so the same zero could be used for both in most cases. Zeroed around 175 yards, you would be in the kill zone out to 200 yards without holding under or over.

Also useful to reloaders is the Remington 260 grain Core Lokt Ultra Bonded bullet with its .144 ballistic coefficient. Core Lokt bullets have a strong reputation for being consistent performers. They may not be the flashiest new technology, but they have been working reliably for generations. They perform well at modest velocities, and it is hard to go wrong with a Core Lokt in any caliber.

This is a good tree-stand cartridge, and should roll up a pig nicely. Within reasonable ranges it will be fine for black bear, elk, or moose. It does not have quite as flat a trajectory as some of the others, but this is not a long-range cartridge anyway. Even if velocities are low for reliable expansion at longer ranges, a .45 caliber bullet doesn’t usually need much expansion.

For loaded ammo, Remington makes their 260 grain Premier Accutip. It certainly looks cool, but I can’t find the ballistic coefficient specs for this bullet anywhere. With a muzzle velocity of 2180 feet per second, Remington says it is the most accurate .45 caliber bullet ever made. It looks like this bullet performs on game about the same as the Hornady FTX bullet does, so it should be fine for anything up to moose or black bear. Like Remington’s Golden Sabre loads, this one has a brass jacket that is cut for expansion.

Setting Up the .450 Bushmaster

My introduction to Big Bore ARs was more luck than general curiosity.  A few years ago, the Indiana Department of Natural Resources added three very popular hunting cartridges to its deer hunting approved list.  The 450 Bushmaster, .458 SOCOM and .50 Beowulf made their way into regulation.  I’d imagine every Hoosier with an AR started salivating at the opportunity of using his or her AR to hunt deer.

It took me several months of research to decide on which big bore caliber upper to purchase.  At first, I was set on the .458 SOCOM, but at the time, ammo availability and pricing held me back from going that route.  The 450’s strong following, ammo availability and pricing won me over and the rest is history.

I ordered the 450 Bushmaster upper from Rock River Arms since it works with my standard mil-spec 5.56/.223 receiver. No modification of the lower receiver was necessary and it comes with a 5 round Bushmaster magazine with a 450 follower.  I had an extra EOTech XPS Holographic Sight available, so my upper setup was done within minutes.

The Hornady 250 grain bullet I used provides a flat trajectory out to 150 yards. With a fifty yard zero the the drop is only 1.7″ at 150 yards.  With a 175 yard zero, it stays just inside the kill zone from 2.7″ high at 100 to 2.5″ low at 200 yards. This is an excellent setup for deer hunters who use tree climbers and shoot within a limited range.  There is no need to memorize hold overs.  Just point and shoot!

After months of waiting it was time to get some trigger time with the 450.  The ballistics tables will only tell me so much and I was really curious how a “big bore” rifle would shoot.  Admittedly, the ammo itself is visually intimidating and the stories I’d heard of this beast had me a little apprehensive.

My range day with the 450 was very different from what I’d expected.  The anticipated bang and shock was nothing close to what I’d imagined.  Much of the felt recoil was mitigated by the factory installed Izzy Muzzle Brake.  My zero session at 50 yards was fun and effortless.  I followed up with another half a dozen shots at 100 yards just for good measure.  The “big bore” weapon system’s setup and Hornady accuracy gave me a strong sense of satisfaction and confidence.  The real test was in November, deer hunting in Indiana. Here’s where the performance really showed >>>

Editor’s note: Special THANKS to Dylan Saunders for his assistance with this story.

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