Background

DEVELOPMENT GOALS

  • A big bore hunting cartridge delivering effective terminal performance on medium to large North American game animals including Deer, Hogs, Elk, Moose and Bear within 200 yards.
  • Once zeroed, able to place a bullet at all ranges from muzzle to 200 yards, into a 6-inch diameter vital area without hold over or sight adjustments.
  • All performance levels achieved using a 16-inch barrel that provides a compact platform for hunting in brush and dense cover.
  • Take advantage of existing technology and systems to deliver a common sense and practical solution, not create a proprietary system that complicates ownership for the end user and / or creates a dependency on a single manufacturer to supply key components or replacement parts.
  • The rifle and the cartridge must be matched in capability.

PLATFORM SELECTION

Given the expansion of 308 WINCHESTER based AR series rifles during the past decade including new products from DPMS, Colt, Smith & Wesson, Ruger, Sig and H&K, the decision to move beyond the AR-15 became obvious and take Big Bore AR performance to the next level without being restricted by the limitations of AR-15 platform.  Most notably, in the AR-15, as the bolt face is opened, the operating pressure of the cartridge must be reduced to limit the bolt thrust to prevent premature bolt failure.   As you reduce operating pressure to accommodate the weakness of the AR-15, you create a situation where it is possible to overload the cartridge, exceeding the limits of the rifle, while not reaching the point that the cartridge case gives the hand loader indications of pressure.   Fore example, a brass manufacture may construct the brass to have an operating pressure of 62,000 PSI, but due to AR-15 bolt thrust limitations, the maximum loaded operating pressure in the AR-15 must be limited to 52,000 PSI.  Since the cartridge case is constructed to operate at 62,000 PSI, it will very likely not show any indications of pressure to that is exceeded.   By going to the 308 WINCHESTER based AR rifle and using a 308 WINCHESTER based cartridge case, the rifle and cartridge are matched in capability and a higher margin of safety is achieved.

Performance wise, 308 WINCHESTER based AR series rifles were chosen because if you are seeking a Big Bore, you are seeking power to do a job and that job often is hunting large and / or dangerous game, which is no time to mess around with reduced performance by limiting yourself to the AR-15 platform and its weaknesses.

CARTRIDGE CASE & CALIBER DECISION PROCESS

Once the decision was made to go with the .308 Winchester AR platform, not the AR-15, multiple calibers were considered including 44 (.429), .45 (.451-.452), .458, .475 and .499.     In modeling the different calibers, it was determined to limit the case length to 1.800 inches, which would make the cartridge legal for rifle hunting in the State of Indiana.

Various case designs were considered ranging from a .473 rim / taper or straight case to a .473 Rebated Rim up to a .532 magnum rim diameter.   Following a thorough consideration of all the implications of each design, the decision became clear of what caliber and case design would provide the best performance while minimizing the need to create new hardware that would complicate the manufacturing of rifles.

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45 RAPTOR Brass may be purchased by emailing:

arne@northamericansportsman.com