A Bushmaster With A Big Bite continued from page 1

Platform Placement

The beauty of the .450 Bushmaster rifle and carbine is that, from the outside, they look a lot like any other AR. Despite the size of their bores, the two models retain the qualities that make the AR such a fast-handling firearm. The rifle, with its 20-in. barrel, has an overall length of 391/4 ins. and weighs 81/2 lbs. The carbine's 16-in. barrel cuts its overall length down to 351/4 ins. and makes its weight closer to 8 lbs. Both the rifle and carbine have forged 7075-T6 aluminum receivers with a matte-black, hard-anodized finish. The dimensions of the receivers are standard, except for the ejection port. To ensure there is ample room for the fat .450 Bushmaster cartridges to clear the upper receiver, the guns have an enlarged ejection port that measures .540 in. wide. Both models have a flat-top upper with a Picatinny rail to make mounting optics easy. Their A2-style buttstocks and pistol grips should be familiar to anyone accustomed to shooting an AR, and the fire controls remain in the conventional places.

Although the .450 Bushmaster Rifle utilizes a carbine-length gas system, it retains a non-functioning gas block at the front of the forearm. Shooters can attach aftermarket accessories to the false gas block.

The .450 Bushmaster cartridges are held in a single stack in the magazine. To load the magazine, the cartridges must be slid beneath the feeding lips, not simply pushed down like .223 Rem. cartridges in a standard M16 magazine.

The heavy-contour, chrome-molybdenum barrel is .742 in. in diameter and features an Izzy-style muzzle brake. It is button-rifled with a 1:24-in. twist and has a chrome-lined bore and chamber. The barrel is free-floated inside an aluminum fore-end, which also houses a carbine-length gas system on both models. Bushmaster found the rifle functioned more reliably with a carbine-length gas system, and production is easier when both models use a gas tube of the same length. However, the rifle retains a non-functioning gas block at the front of the fore-end to allow the installation of aftermarket accessories. The tubular aluminum fore-end is vented to help dissipate barrel heat. Checkering that wraps around its circumference ensures a firm purchase. The fore-end sports a sling swivel stud, another of which is found on the buttstock.

A few modifications to the internal components enable the rifle and carbine to handle the .450 Bushmaster cartridge. First, the bolt face is widened to .475 in. It works in conjunction with an extractor and ejector developed to accommodate the larger cartridge size. To help the cartridges reliably enter the chamber, the feeding ramp is also enlarged.

Although .450 Bushmaster magazines have the same dimensions as standard M16 magazines, the cartridge's size mandates a single-stack arrangement. A blue follower specific to the .450 Bushmaster round cradles the row of cartridges in the magazine. Capacity is drastically reduced. A magazine that holds 30 rounds of .223 Rem. will accommodate nine .450 Bushmaster cartridges, and a 20-round magazine's capacity is lowered to just five. You'll get only three .450 Bushmaster rounds in a magazine that would normally hold seven more .223 Rem. cartridges.

Unleashing the Beast

I will admit that at first I was a bit apprehensive of settling down behind the .450 Bushmaster on the bench. "Watch out for that A2 buttplate," warned a fellow editor. "After more than a few shots, it turns into a meat tenderizer." Preferring that my shoulder stay un-tenderized, I made a mental note to use a Caldwell Lead Sled during accuracy testing.

The .450 Bushmaster is capable of outstanding big-bore accuracy, as demonstrated by this five-shot, 100-yd. group that measures less than 11/4 ins.

First, though, I had to equip the rifle with a scope. Neither the rifle nor the carbine chambered in .450 Bushmaster comes with iron sights. Thanks to the Picatinny rail, I had a Nightforce NXS 2.5-10x24 mm scope attached in no time.My first session with the .450 Bushmaster was on NRA's indoor test range to zero the rifle and chronograph the Hornady ammo. Yep, I started with the rifle on the Lead Sled, partly to gauge its thump and partly because I seem to get more consistent chronograph results with the rifle cradled in the solid rest. The 10 shots for velocity didn't seem at all painful, but then the Lead Sled does a wonderful job of soaking up recoil.
   Switching to just a sandbag rest under the fore-end and another under the buttstock, I was pleasantly surprised. Felt recoil was comparable to that from a .308 Win. After I zeroed the rifle I shot several more groups, and at 50 yds. I was impressed at the gaping, cloverleaf-like holes the bullets punched in the paper.
   The next trip was to the local 100-yd. range for serious accuracy evaluation. Although the trigger pull was a bit heavy at 5 lbs., 10 oz., and had some creep, the rifle turned in a very respectable performance. I had only the 250-grain FTX load—Hornady's initial offering—but the rifle liked it. After five, five-shot groups from a sandbag rest, the average group size was right at 11/2 ins. The .450 Bushmaster was even more enjoyable to shoot offhand. With the Nightforce turned down to 2.5X, I emptied several magazines into an 8-in. target at 50 yds. Recoil felt more like a prolonged shove than a sharp kick, and shot-to-shot recovery was faster than I expected.

The bolt of the .450 Bushmaster Rifle is standard, except for an enlarged face and specialized extractor and ejector designed to handle the cartridge's large rim diameter.

While the .450 Bushmaster rifle had no trouble proving it was accurate, it did have a few problems with feeding. On several occasions, the bolt failed to completely seat. A couple of firm taps on the forward assist usually fixed the hang up, although twice I had to resort to clearing the chamber and starting with a fresh round from the magazine. The five-round magazine, too, was somewhat finicky. At times the feed lips did not want to hold the top cartridge in the correct position. They appeared to be in fine condition, but even a slight bend could have caused the problem. A new magazine may have been just the ticket, but only one was supplied with the rifle. There were no failures to eject throughout testing. Cartridges were thrown briskly to the rear at about the 4:00 position in relation to the ejection port.

Big Fun

With ARs becoming increasingly popular for big game, the .450 Bushmaster may prove to be an effective hunting cartridge. It packs enough punch to take just about any North American game animal, except perhaps the big bears. It very well may be the hog hunter's dream. The short overall lengths of both the rifle and the carbine would make them well suited for close work in heavy cover. It is certainly accurate enough for shots on game at 200 yds. or more, and with a carefully considered zero, you'll be able to hold dead-on to at least 200 yds.

The fun factor of sending 2,250 grains of lead downrange as fast as your trigger finger will allow is another consideration. Target shooting just seems to be more fun when you can see the bullet holes in the paper with the naked eye. The .450 Bushmaster adds even more versatility to a platform that has already been adapted to a host of applications. It's a well-balanced cartridge-and-firearm combination that offers fun in a big way.

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Bushmaster Firearms
(800) 883-6229
www.bushmaster.com

Hornady
(800) 338-3220
www.hornady.com

Nightforce Optics
(208) 476-9814
www.nightforceoptics.com