April 29, 2021
By Jake Edmondson
A few years ago, several states in the upper Midwest changed their hunting regulations to now allow straight-wall metallic cartridges larger than a specified caliber for hunting whitetails. One such cartridge currently surging in popularity is the .450 Bushmaster, and one of the newest models to come to market is Mossberg’s Patriot Predator. More about it later.
Introduced by Bushmaster and Hornady in late 2007, the .450 Bushmaster cartridge was initially an attempt to improve the ballistic performance of AR-15 rifles. It launched a .45-caliber, 250-grain bullet at a muzzle velocity of 2,200 fps, which was definitely a step up in performance compared to the 5.56 NATO’s 55-grain bullet at 3,200 fps. At the time the .450 Bushmaster was introduced, not many folks hunted with an AR-style rifle, but things have certainly changed since then. A lot of rifle manufacturers have adapted their offerings, including ARs, bolt actions, and single shots, to chamber the .450 Bushmaster.
The .450 Bushmaster case is based on the .284 Winchester, which has a fat, 0.500-inch base, almost as large as the belted magnums, and a rebated rim that is the same diameter as the .30-06 (0.473 inch). The case body has a slight taper, and after some modifications, today’s .450 Bushmaster has a case length of 1.700 inches, a cartridge overall length (COL) of 2.260 inches, and a maximum average pressure (MAP) of 38,500 psi. The round uses Small Rifle primers and 0.452-inch-diameter bullets. It was accepted by SAAMI.
Back in 2007 Hornady was the only source for factory-loaded ammo, but now Remington, Federal, and Winchester also offer it. And today there is a plethora of handloading components for it, including unfired cases, primers, powders, bullets, and reloading dies from a number of sources. Load data is plentiful, and the 2021 edition of the Hodgdon Annual Manual contains a special report written by Bryce Towsley that includes the .450 Bushmaster. I encourage readers to pick up a copy of that special publication if they want to get some good handloading tips.
The new .450 Bushmaster Mossberg Patriot Predator carbine has a 16.25-inch-long, threaded barrel (11/16-24 TPI), and a thread cap is included. The barrel tapers from a diameter of 1.17 inches ahead of the receiver to 0.76 inch about an inch from the muzzle end. At that point it flares out to a diameter of 0.82 inch. Twist rate is one turn in 24 inches.
The synthetic stock is Flat Dark Earth in color and has a 1-inch-thick black recoil pad and sling-swivel studs on the fore-end and the buttstock. It has subtle texturing on the grip and the foreend. The metal has a utilitarian matte blued finish, according to Mossberg, but I think it looks more like matte black.
The push-feed bolt action works effortlessly, and lockup is courtesy of two lugs. The bolt body is spiral-fluted, and the bolt knob is large and checkered at the business end.
The two-position safety is located at the rear of the receiver on the right-hand side. It does not lock the bolt, so the rifle’s chamber can be unloaded with the safety engaged.
The trigger is Mossberg’s LBA (Lightning Bolt Action) trigger that is user-adjustable from 2 to 7 pounds. The mechanism has a safety lever within the trigger’s finger piece that must be pressed before the trigger can be fully squeezed. It’s similar to the type of trigger found on a lot of other pistols and rifles these days. Straight from the box, the trigger on the review sample carbine averaged 2 pounds, 12 ounces, and it was crisp and clean.
I didn’t adjust the sample gun’s trigger pull, but it’s simple to do. Here’s how to do it. Remove the barreled action from stock by unscrewing the front and rear action screws. The trigger pull adjusting screw is located on the front of the trigger housing above the finger piece. To increase trigger pull, turn the screw clockwise. To decrease the trigger pull, turn the screw counterclockwise. The adjusting screw incorporates a nylon patch that provides resistance while turning the screw, and Mossberg cautions users to not turn the screw counterclockwise beyond flush with the trigger housing. If the trigger pull adjusting screw protrudes beyond the surface of the trigger housing, damage to the stock may occur during reassembly. Mossberg also warns to not remove the Trigger Pull Adjusting Screw or the Adjusting Spring from the trigger housing. The components may get lost and trigger pull adjustment will not be possible.
When reinstalling the action into the stock, tighten the front action screw first and then the rear action screw. With the firearm pointed in a safe direction, visually and physically inspect the chamber and magazine to make sure it is unloaded, and then perform a function test. If the trigger pull isn’t satisfactory, repeat the procedure.
The .450 Bushmaster Patriot Predator’s box magazine holds four rounds. And this new version of the Patriot Predator comes with a Picatinny receiver rail and rifle sights. The front sight has a bright red fiber-optic insert, and the rear sight is fully adjustable for both elevation and windage.
Without a scope, the Patriot Predator weighs 6.5 pounds. With the Leupold VX-Freedom AR 1.5-4X 20mm scope I installed with a set of quick-detach scope rings on our sample carbine, the rig weighs less than 7.5 pounds. Even though it’s intended for AR-15s, I think the scope is a perfect choice for this woods-and-timber-hunting bolt action. (See the accompanying sidebar for more about it.)
By the way, in an 8-pound rifle, .450 Bushmaster loads generate between 9 ft-lbs and 15 ft-lbs of recoil. That’s pretty similar to typical .30-06 rounds, which generally range from 10 ft-lbs to 20 ft-lbs, so most hunters should be able to handle it.
Mossberg Patriot rifles have earned a reputation for achieving very good accuracy despite their low retail prices. Previous Patriots in other calibers that Shooting Times has reviewed have produced 100-yard group averages ranging from less than an inch to a little over two inches depending on the caliber and the load. That’s with factory loads and handloads. The new .450 Bushmaster Patriot Predator is in line with those results. It’s also very handy, due to its compact overall length and manageable weight.
The popularity of the .450 Bushmaster is on the upswing due to new ammunition and new guns like the Mossberg Patriot Predator. It’s a fine choice for hunting whitetails, black bears, and hogs out to 200 yards or better, and it can do the job on even bigger game with the right bullet. If you don’t believe me, check out that article by Bryce Towsley in the 2021 edition of the Hodgdon Annual Manual.
Mossberg Patriot Predator Specs
TYPE: Push-feed bolt-action repeater
CALIBER: .450 Bushmaster
MAGAZINE CAPACITY: 4 rounds
BARREL: 16.25 in.
OVERALL LENGTH: 35.5 in.
WEIGHT, EMPTY: 6.5 lbs.
LENGTH OF PULL: 13.75 in.
FINISH: Matte blued barrel and receiver, Flat Dark Earth stock
SIGHTS: Adjustable rear, fiber-optic front, Picatinny rail
TRIGGER: 2.75-lb. pull (as tested)
SAFETY: Two position
MANUFACTURER: O.F. Mossberg & Sons; mossberg.com