Reloading 7mm Mag
The 7mm Remington Magnum is one of the great all-around
rifle cartridges and the most popular magnum cartridge yet devised. It has one
of the highest reputations among hunters, especially those hunting big game.
Ammunition for the 7mm Remington Magnum is manufactured not
only in North America, but also in Australia, Europe, Africa and possibly other
countries we don’t know about. It is very widely distributed and can be
purchased in most countries where big game is hunted. The original factory
loads for the 7mm Rem. Mag. were (and are) a 150 grain spitzer bullet at a MV
of 3,110 fps and a ME of 3,221 ft. lbs., and a 175 grain spitzer bullet at a MV
of 2,860 fps and ME of 3,178 ft. lbs. Remaining energy at 300 yards with the
150-grain bullet is 1,792 ft. lbs.; with the 175 grain bullet it is 1,956 ft.
In addition, factory loads with 139-140 grain bullets at
3,150 fps, a 154 grain bullet at 3035 fps, 160-162 grain bullets at 2,940 fps,
a 165 grain bullet at 2,900 fps, and 170 grain bullets at 3018 fps have been
added. This is a pretty good selection of factory loads for big game hunting.
Handloaders need to know that the correct bullet diameter is
.284", maximum COL is 3.29", and maximum case length is 2.50".
The SAAMI MAP for Remington's Big 7 is 52,000 cup.
Reloading brass for the 7mm Rem. Mag. can both save money
and allow the shooter to develop accuracy loads for his particular rifle, which
the big loading companies obviously cannot do. Reduced loads for practice or to
reduce blast and recoil are also possible.
Naturally, magnum primers and the slower burning powders,
starting at about the burn rate of IMR 4350, are best in this big case with all
bullet weights from 120 grains on up. IMR 4831, H4831, H1000, Win. WMR, and
RL-22 are recommended powders for most big game hunting applications.
7mm (.284") bullets are available in a wide range of
weights and styles. Hornady offers bullets from 100 to 175 grains, for
instance, which is typical. Bullets from 139-162 grains are the most popular
with reloaders. Like most 7mm Magnum cartridges, a bullet weighing around 150
grains is about optimum for all-around use in the 7mm Rem. Mag. For example, I
use the Hornady 154 grain Interlock SP bullet at a MV of about 3000 fps for my
all-around 7mm Rem. Mag. load.
The Hornady Handbook of Cartridge Reloading, Sixth
shows that with their 139 grain bullets, 57.2 grains of WMR
powder gives a MV of 2700 fps, and a maximum load of 70.3 grains of WMR gives a
MV of 3200 fps. These are deadly, long range loads for CXP2 class game. Hornady
used their own brass and Win. WLRM primers for these loads, which were tested
in a 24" rifle barrel.
The fifth edition of the Nosler Reloading Guide reported
that IMR 4831 was the most accurate powder with their 150 grain bullets. 61.0
grains of IMR 4831 behind a 150-grain bullet gave a MV of 3020 fps, and 65.0
grains of the same powder gave a MV of 3240 fps. These loads used Winchester
cases and Federal 215 primers and were chronographed in a 24" rifle
160-162 grain bullets are popular choices for heavy game
with the 7mm Rem. Mag. The
Speer Reloading Manual, Number 13 shows
that 61.0 grains of RL-22 can drive their 160-grain bullet at a MV of 2773 fps,
and a maximum load of 65.0 grains of RL-22 yields a MV of 2976 fps. These
velocities were taken in a 24" pressure test barrel and used Remington
cases and CCI 250 primers.