QUALITY CARTRIDGE CAN SUPPLY
BRASS FOR THE .500 PHANTOM AND THE REAMER AND HEAD SPACE GAGES
MAY BE OBTAINED FROM MANSON PRECISION REAMERS.
As with the "smaller" .458 SOCOM AWS, the .500 Phantom AWS was designed to meet specific
criteria when deployed from a specific weapons platform. Whereas the .458 SOCOM was designed for use in the AR-15 platform, the .500 Phantom is intended for the larger AR-10 platform. Basic criteria were the use of unmodified magazines and lower receivers, minor modifications to the upper receiver and bolt group, and minimal changes to outward appearance. In addition, the largest feasible case that would function reliably, as well as the use of .510 caliber projectiles and sabots were requirements set forth by the project sponsor.
(L to R) .308 168 gr in sabot, 500 gr. Hawk, 570 gr. Barnes XLC,
700 gr Hawk, 650 gr. GI M2 Ball, seated, 308 Winchester
The initial design, dubbed the .510 Phalanx, used a 2.00” long case with the largest available case diameter outside of the .50 BMG cartridge. A heavily rebated rim and prominent shoulder for headspace control were included in the design as well. Several prototype cases were formed, and ballistic simulations predicted acceptable performance. Unfortunately, however, quality of the brass for the prototypes left to be desired and the project was initially shelved. Pictured below
shows the 500 Phantom being formed.
(L to R) 500 Jeffery, Shortened, Formed, Trimmed,
Seated 700g Hawk Spz, 308 Winchester
With the arrival of a new project sponsor,
the idea was brought back to life, and a different case
design was proposed. By going to a slightly smaller
diameter case, a more prevalent parent case of improved
quality could be used. Furthermore, the case length was
reduced to 1.535” for two reasons: To be able to employ
the .50-to-.30 caliber sabot and still meet desired
overall loaded length of 2.75”, and the ability to
employ the 750-grain Hornady A-Max bullet and meet desired
overall loaded length of 3.34”. Two additional changes
were incorporated, namely the use of the standard magnum
rim size, and strengthening of the web to be able to
operate the cartridge at higher pressures.
Top, DPMS LR-300 mag with 700 gr. Hawk.
Bottom, AR-10 mag with 168gr. .308 in sabot....
The cartridge will function from standard
AR-10 lowers and magazines, and the 20-round OEM magazine
will accept at least 6 of the Phantom cartridges. The DPMS
LR-308 rifle can also be modified to accept this
cartridge. By using the standard magnum rim size, the OEM
bolts designed for use with the WSM or RSAUM line of
cartridges can be used without further modification.
Existing upper assemblies can be converted to .500 Phantom
by rebarreling and adjusting the gas system.
In addition to the gas operated AR-10 and LR-308,
standard and short length bolt action rifles can be modified to
accept this new cartridge. With the prevalence of the WSM and
RSAUM line of cartridges, any bolt action rifle chambers in any of
those cartridges can relatively easily be converted to the .500
Performance tests and initial prototyping were
performed using an AR-10 with 24-inch Pac-Nor 1-in-9 twist barrel.
The barrel was equipped with a JP Enterprises Recoil Eliminator
muzzle brake, JP free floated hand guard, and SPR pistol grip. The
starting loads were developed using QuickLoad internal ballistics
software, and maximum operating pressure set at 50,000 psi.
While load development continues, initial
results show all criteria were met if not exceeded. A
sampling of the results is given below. (Velocities were collected using a F-1
Chrony, and groups were measured at 100 yards. )
|Barnes 300 gr FN
|HAWK 500 gr Spitzer
|Barnes 570 gr XLC
|M8 649 gr API
|Hornady 750 gr AMAX
For anyone looking for the ultimate in gas
operated shoulder fired power, the .500 Phantom should fit the
bill. Formed and headstamped brass is available from Garber Supply
Company, reloading dies are available from CH 4 D, and bolt action
rifles in this caliber can be ordered through Sportsmans Guns.
ONE OF FOUR CUSTOM BUILT
AR-15 (!!!) UPPERS IN .500 PHANTOM, USING OLYMPIC ARMS WSSM
COMPONENTS AND OUR CUSTOM MUZZLE BRAKE.
THE FEISTY ROOSTER's GUN PAGES
I enjoy shooting. I really enjoy shooting something unique. While I appreciate the
simple, unspoiled pleasure in shooting a .243, a 30-30 or a 30-06, my secret joy
comes from atypical cartridges. I've begun to list some of them below. Hopefully
this list will grow to include a magical collection of the useful, unusual and the exotic.
Be sure to visit the
second home of the 500 Phantom
FOR MORE INFORMATION CONTACT US AT Info@TEPPOJUTSU.COM