Darrell Does 2500 Yards — With a .338 Allen Magnum
What cartridge would your chose to hit targets at long range … extremely long range, as in 2500 yards? Well, for ace competitive shooter Darrell Buell, the answer is the .338 Allen Magnum, a .408 Cheytac necked down to .338. This “super-sized” cartridge flings .338-caliber, 300-grain Berger Hybrid bullets at 3450 fps. That delivers some impressive ballistics at ultra-long range. Darrell got to “test-drive” a .338 Allen Magnum rifle at 2500 yards (1.42 miles) while teaching a Long-Range Seminar at the Legion Operator Training Group (OTG) Facility in Blakely, Georgia.* The rifle belonged to Christopher Sykes.
Shown below is the 338 Allen Magnum (AM) next to a .308 Winchester round loaded to an extremely long OAL. The .338 Allen Magnum is a wildcat based off the .408 Cheytac (Cheyenne Tactical) parent case. The cartridge’s inventor, Kirby Allen, states: “The .338 Allen Magnum, when loaded with a 300gr SMK, offers a legit 500 to 600 FPS velocity advantage over the 338 Lapua Magnum”.
Darrell says: “Yeah, it’s a beast [but] with that brake, it kicks less than my .308 competition rifle. It’s got more energy at 2500 yards than a .45 ACP has at the muzzle. The .338 Allen cartridges are standing next to the SEB Joy-pod, along with a standard .338 Lapua Magnum cartridge. With the excellent muzzle brake on the .338 Allen, I could spot my own hits with just the slightest twitch of the joystick. The rifle was not particularly heavy, consequently the pod would hold the crosshairs where you left them without a hand on the joystick.”
Caduceus explains: “I can use the .308 version of the RCBS Precision Mic to compare brass which has been fully sized in my 6BR body die with brass which has been fired in my chamber. With the spacer inserted, FL-resized cases mic 0.000″ at the datum point on the shoulder. Using the same set-up, fire-formed cases measure +0.005″. In other words, my chamber has a headspace of +0.005″ above minimum dimensions. This is fairly typical of a custom rifle set up for switch-barrel use. If I were to FL-resize my brass down to minimum spec each time, this excessive working would shorten its life-cycle and might lead to case head separation. Now that I know the headspace of the chamber, I can substitute the standard shell holder on my press with a Redding +0.004″ competition shell-holder. This ensures that my cases only receive 0.001″ of shoulder set-back.”
