Xtreme Machining .338 Xtreme Tactical Rifle

posted on August 7, 2009

The .338 caliber is fast becoming the hot bullet size for long-range precision rifles-and for good reason. Match-grade bullets in that caliber, such as the 250-gr. Lapua Scenar and 250- and 300-gr. Sierra MatchKings, have higher ballistic coefficients than virtually any smaller-diameter projectile, and thus have flatter trajectories and are less subject to wind deflection. Interest in the .338 is largely the result of the success of the .338 Lapua Magnum. Its ballistics are indeed impressive-a nominal 2960 f.p.s. muzzle velocity, and nearly 5,000 ft.-lbs. of muzzle energy, with 250-gr. bullets. Yet the performance gap between the .338 Lapua and the venerable .50 BMG is still wide.

In 2008, Xtreme Machining of Grassflat, Pa., introduced a novel .338 cartridge and rifle to narrow that gap. The new round, christened the .338 Xtreme, was the result of a developmental collaboration between Xtreme Machining proprietor and master machinist Bob Zelenky, and ballistic experimenter Olan London. Both men were highly experienced 1,000-yard benchrest and .50-cal. competitors, and Zelenky had been producing precision actions, stocks and rifle accessories for years, so they were well-qualified to embark on such an ambitious project.

The .338 Xtreme cartridge is based on the huge .505 Gibbs case necked down, strengthened and given a sharper 35-degree shoulder. Full-case capacity of the .338 Xtreme is 161 grs. of water. But the new round is much more than an oversized .338 Lapua. Maximizing the performance potential of the large case is a new bullet, a 266-gr. lathe-turned tellurium-copper alloy projectile with a boattail shape that confers a ballistic coefficient of 0.825-significantly higher than that of any other .338-inch-diameter production bullet. This bullet has a unique, patent-pending, two-diameter design with a forward bearing portion measuring 0.331 inches, or about 0.001-inch more than land diameter, and a short driving band just forward of the boattail that opens up to 0.338 inches, and thus completely fills the grooves. The unique design reduces bore friction and chamber pressure, increases velocity, and gives enhanced accuracy as a result of better initial bullet alignment with the bore.

Brass for the .338 Xtreme is produced by Bertram Bullets of Australia, and loaded cartridges are produced by International Cartridge Corp. of Reynoldsville, Pa. Standard chamber pressure for factory ammunition is 61,100 p.s.i., producing a nominal 3350 f.p.s. muzzle velocity out of 30-inch barrels.

A new, oversized rifle action was necessary, with a 1.600-inch-diameter receiver of 420 stainless steel and a two-lug bolt of 4140 steel for a 0.800-inch body. Also needed was an oversized barrel measuring 1.400 inches at the receiver ring for maximum strength and hardness. Zelenky bores, rifles and heat-treats his own tubes from 416 stainless steel. Rifling is in a six-groove, 1:10-inch, right-hand twist, with six longitudinal flutes and a choice of 26- or 30-inch lengths.

Although the absolute chamber pressure for the .338 Xtreme is no greater than that of other modern high-performance rounds, the size of the case increases the area of the chamber walls on which this pressure can act. Since steel's tensile strength increases with hardness, Zelenky elected to harden all critical components to a higher level than is usually found: 44-46 Rc for the receiver and bolt, and 35-37 Rc for the barrel.

Features of the Xtreme Tactical's action include a 4.49-inch-long ejection port, a pivoting bolt release mounted on the left side, and pinned 0.250-inch-thick recoil lug. Each Xtreme Tactical rifle receiver is topped with a 40-minute Picatinny scope rail for long-range shooting. The bolt head is fairly conventional, but immensely strong, with two massive lugs, a spring-loaded plunger ejector, and a Sako-style extractor. Rifle Basix triggers with a pull weight of about 3 lbs., 4 ozs. are standard.

Stock options for the rifle include the A-5 tactical unit from McMillan Fiberglass Stocks using Xtreme Machining's own bottom metal, and the modular aluminum unit from McRee's Precision. The latter is designed to allow easy attachment of a host of tactical accessories, including night vision adapters, and is also available in a folding version that reduces total gun length (with a 26-inch barrel) to about one meter (39 inches). Additionally, single-shot target models can be ordered with a laminated-wood benchrest-style stock. With all stocks, the Xtreme Tactical's barrels are fully free-floated.

The .338 Xtreme Tactical and its cartridge were designed to surpass the performance of the .338 Lapua in every respect, including effective range. With a claimed accuracy of 1 m.o.a. or less at ranges beyond 2,300 yards, the gun begged for testing at ranges well beyond our "Dope Bag" standard distance of 100 yards. Although no 2,000-yard facility was readily available, we were able to safely test the gun at 1,500 yards on a private range.

Firing was done from the prone position using a Harris bipod and Protektor and Red-Tac rear bags for support, simulating the firing position that would be used under tactical conditions. Targets were 17-inch Birchwood Casey Shoot-N-C bullseyes on large, 48-inch-square backing boards. Sighting was by way of a Nightforce 8-32x 56 mm NXS scope. Range conditions were sunny but windy, with variable gusts exceeding 25 mph at times, with no wind flags or other indicators to reveal what was happening in the nearly one-mile space between the firing line and the target. Nonetheless, Xtreme Machining's accuracy standard of 1 m.o.a. was achieved-and bettered.

Group dispersion was generally in the lateral direction, clearly indicating the influence of the wind. Under those conditions, the fact that average group size was kept to slightly larger than 14 inches was a testament to the aerodynamic qualities of the cartridge's 0.825-B.C. copper bullet-and, of course, the skill of our test shooters. Shooting tests we witnessed at other times, with better conditions, using scopes from Nightforce and U.S. Optics, showed that the .338 Xtreme Tactical is typically capable of 0.75-m.o.a. or better accuracy pretty consistently at ranges from 1,000 to 2,000 yards.

Two things stood out in our test-fire sessions. First, we were surprised by the gun's lack of perceived recoil-about what one might experience with a sporter-weight rifle in .243 Win. or .260 Rem., and attributable to the effective 42-port Xtreme Machining brake. And second, we found the rifle remarkably comfortable and tolerant of minute differences in shooting technique. Accuracy and stability are excellent with current 1:10-inch-twist barrels.

With a flatter trajectory, less wind deflection and 30 percent more muzzle energy than the .338 Lapua, the .338 Xtreme Tactical offers a blend of accuracy, power, range, manageable weight and low recoil that is equaled by few, if any, factory gun/cartridge combinations. The Xtreme Tactical will be of great interest to 2,000-yard rifle competitors and to all shooters fascinated with state-of-the-art long-range shooting technology.

Manufacturer: Xtreme Machining; (814) 345-6290; Xtrememachining.us
Distributor: American Tactical Imports (ATI), Div. of AmChar Wholesale; (800) 333-0695; Americantactical.us
Caliber: .338 Xtreme 
Action Type: bolt-action, repeating center-fire rifle
Receiver: 420 stainless steel 
Barrel Length: 26", 30" (tested) 
Rifling: Six-groove, 1:10" RH twist
Magazine: Detachable steel box, seven-round capacity 
Sights: None; 40-m.o.a. Picatinny rail mounted on receiver 
Trigger Pull: Rifle Basix; single-stage, 3 lbs., 4 ozs. 
Stock: Laminated wood target; McMillan A-5 tactical; McRee's Precision tactical; dimensions (McRee's Precision stock): length of pull adj. from 13¼" to 151⁄8"; drop at cheekpiece adj. from 1/2" to 11⁄8"
Overall Length: 53" (30" barrel) 
Weight: 15.5 lbs. (McMillan A-5 stock, 30" barrel); 19 lbs. (McRee's Precision folding stock, 30" barrel)
Accessories: 40-m.o.a. rail, hard case
Suggested Retail Price: $4,678 (single-shot, McMillan A-5 stock); $4,834(single-shot target, laminated wood stock); $5,092 (repeater, McMillan A-5 stock); $6,042 (repeater, McRee's Precision folding stock)



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