The Two Faces of Magnum Rifles
                       (c) Copyright 1992   by James V. Doody


Preface
     Some recent discussions on the Hunting Section have mentioned
Magnum hunting cartridges in ways that ignore several objective
ballistic realities.  Although understandable, these comments tend to
perpetuate some false beliefs about hunting with Magnums.  I'd like to
offer my own opinions and some information which I believe to be
physical fact in aid of intelligent decision making by hunters about
cartridge, rifle, and tactics when equipping and otherwise preparing
themselves for the field.

Taxonomy
     I'll be using the term "Magnum" to describe rifles, cartridges, or
loads which deliver a given caliber bullet from the muzzle at a range of
velocities materially higher than "standard" or "moderate".  Although
most such cartridges have belted heads and were designated "Magnum" by
their developers, some may be simply high-velocity loads in more
conventional cases and dubbings.  In general, there are several
cartridges with velocities in this "Magnum" range in any given caliber.

History
     The term "Magnum" for rifles and cartridges was popularized by
Holland & Holland beginning in 1912 with their famous .375 belted
rimless cartridge and the extra-long bolt-action rifles chambered for
them.  These were "small-bore" cartridges of their day intended to bring
low-cost repeating rifles to the kind of African game applications that
had hitherto been the province of single-shot and double rifles in
calibers up to .600.  Over the subsequent decade or so, H&H introduced
other calibers based on the same case and head design and a few of their
British competitors brought out their own belted Magnums.  The .375 and
.300 H&H Magnums are still chambered and loaded by makers all over the
world and have been used to take every species of big game on Earth.
     American makers of rifles and ammunition began to chamber and load
the H&H Magnums almost immediately.  Wildcatters also worked extensively
with the H&H case.  However, it wasn't until the mid-1940s that the
Magnum concept was enhanced and brought to smaller calibers by a
commercial American maker.  Roy Weatherby was the Magnum's missionary.
     Weatherby modified the tapered H&H case by blowing the walls out
almost parallel and restating the shoulder to yield greater powder
volume for a given case length.  He first shortened the case and necked
it down to calibers of .228, .257, .277 ("270"), and .284 ("7mm").
Later, he used it full-length ito make calibers of .308 ("300"), .338
("340"), and .375.  For greater appeal to African sportsmen and
professional hunters, Weatherby developed an even larger belted case
necked to .375 ("378"), .458 ("460"), and .416.  Smaller belted cases
were introduced for the Weatherby .224 and .243 ("240") calibers.
     More than a decade after Weatherby made "Magnum" a magic word to
American hunters and started the company which is still centered around
Magnum cartridges and rifles, Winchester brought out their .458 Magnum
using the case design much like the .375 Weatherby cut off at the
shoulder to accomodate a 500gr .45 caliber bullet with its full
diameter.  This marked the beginning of a flood of Magnums from the
major makers.
     Even before Winchester could neck their new Magnum down to smaller
calibers, Remington stretched the .222 and called the result "Magnum".
Weatherby recovered from being "one-upped" by necking up his huge .378
Magnum case to use the bullets developed for the .458 Winchester in his
ecliptic .460 Weatherby Magnum.  Norma was next, necking the .458
Winchester Magnum down to .358 and .308 calibers.
     When Remington finally introduced a real Magnum, it was nearly a
carbon copy of the 7mm Weatherby Magnum which had been in the market for
almost twenty years.  However, the 7mm Remington Magnum was more widely
distributed and was chambered in popularly priced rifles.  It quickly
rose in popularity to become America's favorite Magnum.
     Remington was far less successful when they radically shortened the
Magnum case and necked it to .264 and .358 for their 6.5mm and .350
Remington "non-Magnums".  These could not really perform with the
Winchester and Norma Magnums in the same caliber because of their small
case.  Indeed, they were outperformed by smaller caliber Weatherby, H&H,
and Winchester Magnums.  Their short cases allowed them to be chambered
in Remington's 600-series carbines but these were far from popular also.
     For their next belted Magnums, the 8mm and .416, Remington returned
to the full-length Magnum case like that of the .300-375 Weatherby and
achieved excellent ballistics.  The 8mm was handicapped by a dearth of
.323 caliber bullets suitable for its Magnum velocities and some
saturation of the mid-calibers with other options.  The .416 met an
evergreen demand for modern, reasonably priced with the ballistics of
the .416 Rigby so beloved by professional hunters.  Weatherby promptly
took advantage of the bullet availability and hunter interest stimulated
by the .416 Remington Magnum to neck the big case from the .378 and .460
Weatherby to .416 for a belted mirror image of the original Rigby number
and their customary few hundred feet per second of catalog advantage.
     Remington also began to catalog several Magnum-equivalent unbelted
wildcat cartridges such as the superb .22-250 which drives a 55gr .224
caliber bullet just about as fast as anything and faster than the belted
.224 Weatherby Magnum.
     Winchester continued their Magnum program by necking the .458 case
to .264 and .338 calibers.  The hot .264 Winchester Magnum propelled a
100gr bullet from the muzzle even faster than the .257 Weatherby and,
although it lacked the sectional density to sustain that initial
velocity advantage, was clearly a powerhouse in the spirit of the Magnum
movement: small bore and ultra-high velocities usable on much larger
game than had previously been regarded as accessible to 6.5mm bullets.
For some reason, however, the .264 Win Mag never caught on strongly
among hunters.  The .338, on the other hand, became a great success even
though it delivered less energy than the .300 Weatherby.  It's ability
to belt big game with a higher-caliber 250gr bullet wiped out the usual
resistance to the Magnum philosophy.  The .338 Win Mag was so successful
that Weatherby necked up the full-length .300 to make the awesome .340
Weatherby Magnum with more than 5,000 ft-lbs of muzzle energy.
     Wildcatters immediately began necking the Winchester Magnum case to
the American-standard .308 caliber but Winchester took seven years to
introduce their .300 Win Mag.  When they did, it had a longer case than
the rest of the Win Mag brood and was a near-twin to the earlier .308
Norma Magnum.  Like the Norma, its modern powders and higher pressures
turned in factory ballistics a bit better than the venerable .300 H&H
but substantially less than the longer .300 Weatherby Magnum.  It has
nonetheless sold well and is chambered in a wide variety of popularly
priced, standard-action rifles.
     In recent years, the .300 Weatherby Magnum has experienced a boom
of popularity.  It is no longer limited to the high-priced, somewhat
gaudy Weatherby Mark V Deluxe rifle but is chambered by nearly every
major rifle maker and quite a few specialty firms as well.  Factory
ammunition is available from Weatherby with bullets of 110, 150, 165,
180, and 220gr weights.  The 150 and 180gr numbers can be had with the
famous and highly suitable Nosler Partition bullets.  Remington loads
180 and 200gr CoreLokt bullets in .300 Weatherby and recently added 178
and 190gr entries in their Extended Range line.  PMC/Eldorado has also
begun to load .300 Weatherby Magnum with ordinary 150 and 180gr bullets
and with the interesting new Barnes X bullets in 165 and 180gr weights.
     The 7mm Weatherby Magnum, although lacking the .300's velocity
advantage over the competition, has also appeared in many more rifle and
ammunition catalogs recently.  The 7mm Remington Magnum and the .338
Winchester Magnum continue to be hot sellers and are loaded or chambered
by most makers who serve the high-powered hunter's market.  The .300
Winchester Magnum, despite its lack of ballistic advantage over other
.30 caliber Magnums, also has a significant following.  Magnums seem to
have a firmly entrenched position in the arsenals of American hunters.

Ballistics
     The Magnum rifle cartridge is of interest to hunters because of its
ballistic characteristics in all three areas: interior, exterior, and
terminal ballistics.  There are, or rather once were, a few other
distinguishing characteristics such as an extra-long cartridge case and
a belted case head but exceptions have developed to most of these.

Interior Ballistics
     Magnum cartridges achieve their other ballistic benefits by use of
a larger powder charge than standard cartridges of the same caliber.  To
accomodate this, Magnum cartridge cases generally have greater volumes
than standard.  Slower-burning powders usually deliver best results from
these outsize cases.  Magnum rifle primers were developed to assure full
and prompt ignition of those bulky, heavy charges.
     Critics of Magnums often discuss "powder efficiency": the delivery
of muzzle energy or velocity per unit of powder consumed.  Magnums are
rarely as powder-efficient as some lesser cartridges in a given caliber.
It would seem that Magnums "waste" a certain amount of powder in favor
of the highest obtainable propellant effect.  This inefficiency adds a
certain cost to Magnums and increases their recoil.

Exterior Ballistics
     In its simplest sense, we've already stated what's different about
the Magnum:  it propels a bullet of any given caliber and weight FASTER
from the muzzle.  For any given bullet, higher muzzle velocity means
higher velocity and flatter trajectory to any given range.  Viewed
another way, it means far greater range for a given amount of bullet
drop and/or needed retained velocity to incapacitate game.
     That latter view means that Magnums can be zeroed for a point-blank
range over an 8-12" diameter killing zone (depending on the species)
well beyond that which most hunters will risk a shot.  That is to say an
aiming zero will exist such that the maximum bullet rise and fall from
the line of aim will be less than the radius of the killing zone until
it travels further than I would ever want to shoot at big game.
     One very important aspect of an extremely long point-blank range is
that it becomes far less critical to estimate range to the game
accurately and entirely unnecessary to guess at how much "holdover" is
required for a level shot.  Since I'm personally rather poor at both
kinds of guesswork, I very strongly appreciate the carefree ability to
lay my crosshairs where I want to make a hole!
     Like trajectory, wind drift for a given cross-range vector is also
a function of time of flight.  If a bullet from a Magnum covers 300
yards in the time it takes a lesser cartridge to reach out to 100 yards,
it follows that it will drift the same total amount in the longer range
as well.  Again, the Magnum's velocities reduce (but do not eliminate)
the guesswork and make "wind doping" less critical to accuracy.

Terminal Ballistics
     Since, at any given range, the Magnum bullet arrives with greater
energy on game and, at relatively close ranges, bullets from Magnums
contact game at much velocities than can be achieved with "standard"
cartridges, much discussion has arisen of the incapacitating effects of
Magnum velocities.
     Both the original Magnums from Holland & Holland and the new wave
of Magnums from Weatherby were marketed as replacements for larger
caliber ordnance.  The advocates claimed extraordinary stopping power
arising from the unprecedented terminal velocities.  One of the common
expressions was "hydrostatic shock" created by these velocities.
     This use of smaller, lighter bullets at super-high velocities is
the origin of the "overkill" calumny against Magnums.  Especially with
lightly constructed bullets intended for more moderate velocities, the
Magnums are capable of inflicting excessive meat destruction at short or
even medium ranges.  Heavier, stronger bullets correct this tendency.

More on "Overkill"
     It really can't be argued that, holding caliber constant, many
standard velocity and even mild cartridges will do the job at close
range just as well as the Magnum.  As the hunter's cliche goes, "they
can't be killed deader than dead".  Beyond the power needed to drop the
game within sight, any excess tends to destroy meat or merely go to
waste.  It also exacts a price on the shooter in the form of recoil.
     Moreover, at short ranges, some hunters prefer to achieve their
required retained energy by use of heavier, larger-caliber bullets at
even lower velocities.  The "brush gun" devotees offer their "bigger
hole" in rebuttal to the "hydrostatic shock" of the Magnum.  The bison
hunters proved that a big, slow bullet could make North America's
largest land animal nearly extinct before Magnums were invented.

Long-Range Shooting
     However, when discussion turns to really long ranges, reference to
Magnum "overkill" becomes frivolous.  Of course, responsible hunting
situations calling for shots of, say, greater than 250 yards are fairly
rare.  By no means is every hunter skilled enough to attempt such shots
no matter what the ordnance.  A good, steady shooting position and rest
can add at least 100 yards to any hunter's effective, ethical offhand
range, though, and conditions of wind and mirage sometimes match the
hunter's extended abilities.
     At that point, I believe the Magnum in the same caliber that'd be
chosen for that game at lesser ranges to be the right equipment for the
job.  I also want a high-quality scope sight with magnification which
can be varied to well over 6X.  The rifle should not be a lightweight
and should be a very comfortable fit because Magnum recoil can otherwise
interfere with the hunter's preparation for a follow-up shot.
     Note that the bullet from the Magnum at long ranges carries no
mythic Magnum 'overkill" to the animal.  It brings its own weight and
construction at the same kind of velocities that standard cartridges
would make possible at shorter ranges.  It also typically drops from its
line of departure about the same amount as the standard ordnance would
at the much shorter range over which it would reach the same velocity.
     Thus, we may think of the Magnums as "long-range, flat-shooting"
cartridges instead of as "hard-hitting, meat-destroying" weaponry.

Bullets for Magnums
     Bullet selection is one of huntings "black arts" and each major
bullet design has a loyal following of hunters who insist on its unique
virtues and who reject all rival claims.  However, most hunters agree
that expansion and penetration must be matched to the species, sex, and
size and must be balanced for satisfactory performance on game.
     Any given bullet achieves that ideal balance of expansion and
penetration over some range of impact velocity.  Common wisdom is to
recommend high-coefficient boat-tailed bullets which retain more
downrange velocity for long-range shots.  Since these tend to break up
or otherwise underpenetrate at the high velocities of close ranges, a
heavier, more strongly constructed bullet is recommended for controlled
expansion in these circumstances.
     This gradation of bullets is a real nuisance.  When game appears at
close range, there may not be time to switch loadings.  Even when time
is not the problem, the noise is prone to startle the game or even
nearby birds or varmints whose flight sends the danger signal.  Carrying
the solids or heavies and switching to long-range loads for a distant
shot may be less risky but is still far from convenient.
     Magnums retain sufficint velocity to expand strongly constructed
bullets out to the longest ranges most responsible hunters will essay.
A long hollow-point boattail is rarely or never necessary when game
hunting with a real Magnum.  On the other hand, round-nose heavies shed
even Magnum velocities very quickly.  Magnums are demanding of bullet
construction!  On the other hand, the best bullets for Magnums are
likely to perform well at both close and distant ranges.  They have
tightly bonded jackets and hard cores.
     The Nosler Partiton, with its H-section of jacket material holding
it together, is a classic Magnum bullet.  The new Barnes solid
copper-alloy X-Bullet should also be outstanding in near and far
performance from Magnum cartridges.  Most of the major bullet makers
have at least one bullet design which they feel serves the needs of
Magnum velocities on game.

Hunters' Choices
     Americans seem to love to hunt North American game with .30 caliber
cartridge ammunition.  Their "standard" .30 caliber cartridge is the
venerable .30`06 Springfield which served as the principal U.S.
military cartridge for half of the XXth century.  In historical and
"genealogical" terms, the .30`06 has had the same kind of influence on
"standard velocity" cartridges as the .375 H&H had on Magnums.  It is
still the standard by which Americans judge other cartridges.
     Even more ancient than the .30`06, the .30/30 Winchester was the
first popular American smokeless powder rifle cartridge and was adjudged
a tremendously "long range" and "high velocity" cartridge in its day.
It is still fairly popular among devotees of Western nostalgia and is
used, primarily in lever-action carbines, to take quite a bit of game
every year.  The .30/30 proves that "they can't be deader than dead" on
deer and black bear and has even dropped such tough species as elk.
     The .308 Winchester is not much more than a .30`06 shortened by
about half an inch to increase the military combat load and to simplify
design and reduce the weight of automatic weapons.  Fifty years of
development in propellants and barrel steels allow the short .308 to
come close to .30`06 ballistics.  It was the primary NATO smallarms
round for a decade or so and still has military application.  For some
reason, it is also not unpopular in bolt-action hunting weapons.
     Until the renascence of the Magnum movement begun by Weatherby, the
standard approach to reaching ranges for which the .30`06 was unsuited
was to neck that grand cartridge down.  The great interbellum wilcatters
began this work on the .30`06 case almost immediately after it became
widely available to recreational shooters.  Full-length and cut-back
cases were used in every caliber for which bullets were available and a
few for which the wildcatters cast their own.
     The first sub-caliber "long-range, flat-shooting" variant on the
.30`06 to be loaded and chmabered by commercial makers was probably the
famous .270 Winchester.  Introduced in the same year (1925) as the .300
H&H Magnum, the .270 offered almost as flat a trajectory with 130gr
bullets as the .300 did with 150gr and retained more than 1,000ftlbs of
energy at 500 yards.  Recoil was far more pleasant and the "Magnum is
overkill" movement found a marvellous stalking horse.
     It would be much longer before the commercial makers would begin to
load the adjacent 7mm and .25 calibers based on the .30`06 case.  When
they appeared, the .280 Remington with 140gr bullets shot almost as flat
as the .270 and hit somewhat harder downrange while the .25`06 Remington
with 120gr bullets was just a bit weaker and not quite as flat as loaded
by Remington-Peters.  Neither cartridge acquired the popularity of the
.270 or, for that matter, of the 7mm Magnums.
     However, the .25`06 was handicapped in factory form by concern over
safety and compatibility with the earlier wildcats.  Handloaders with
modern rifles and powders were able to safely exceed the factory data by
margins significant enough to make the .25`06 among the very flattest
shooting non-Magnum cartridges suitable for taking the primary species
of North American big game.  With two popular 7mm Magnums, there was
less incentive for reloaders to "push" the .280 Remington.

Example
     Lets sample some ballistic information for these popular hunting
cartridges.  I've picked muzzle velocity data from the originating
manufacturer, used 150gr Nosler Partition bullets for all .30 caliber
ammunition except the flat-nosed .30/30, and used factory downrange data
to calculate Ballistic Coefficient for the other rounds.


 Cartridge     Caliber   Area   Gr     SD     BC   MPBR   MPBR   VelM
                                                   +-5"   zero      0

 .300 Wby Mag    0.308  0.075  150  0.226  0.387    415    355  3,600
 .300 Win Mag    0.308  0.075  150  0.226  0.387    384    328  3,290
 .300 H&H Mag    0.308  0.075  150  0.226  0.387    367    313  3,130

 .30'06 Spfd     0.308  0.075  150  0.226  0.387    346    294  2,920
 .308 Win        0.308  0.075  150  0.226  0.387    334    284  2,820
 .30/30 Win      0.308  0.075  150  0.226  0.217    260    224  2,390

 .280 Rem        0.284  0.063  140  0.248  0.390    353    301  2,890
 .270 Win        0.277  0.060  130  0.242  0.372    357    305  3,060
 .25'06 Rem      0.257  0.052  120  0.260  0.362    350    298  2,990


In the foregoing chart, Caliber is in inches, Area in Square Inches,
bullet weight in Gr(ains), SD (Sectional Density) in the usual pounds
of bellet weight per square Calibers, ballistic coefficient as the
normal dimensionless ratio of actual to standard, maximum point-blank
range (MPBR) for a five-inch radius mortal zone and its zero in yards,
and muzzle velocity (VelM) in feet/second.
     Note that even the feeble .30/30 can be sighted at 224 yards to a
point-blank range of 260 yards!   Only beyond this range would any game
hunter need to think about choosing between "holdover" or a more
powerful load.  All the true "high-power" cartridges give point-blank
ranges in excess of 300 yards with the indicated bullets.  The .300 Wby
shoots flat well betyond 400 yards.  All the Magnums support a zero past
300 yards and reasonable handloads probably do likewise for the .30'06
sub-calibers as well.  Lets look at downrange performance when all
rounds are zeroed for their maximum point-blank range.


 Name           Gr     BC   VelM   EnKM   EleM     Vel    EnK    Ele
                               0      0      0     300    300    300

 .300 Wby Mag  150  0.387  3,600  4,316  -1.50   2,909  2,818    3.0
 .300 Win Mag  150  0.387  3,290  3,604  -1.50   2,550  2,165    1.8
 .300 H&H Mag  150  0.387  3,130  3,262  -1.50   2,415  1,942    0.9

 .30'06 Spfd   150  0.387  2,920  2,839  -1.50   2,236  1,665   -0.5
 .308 Win      150  0.387  2,820  2,648  -1.50   2,150  1,539   -1.4
 .30/30 Win    150  0.217  2,390  1,902  -1.50   1,395    648  -12.6

 .280 Rem      140  0.390  2,890  2,596  -1.50   2,309  1,657    0.1
 .270 Win      130  0.372  3,060  2,702  -1.50   2,329  1,565    0.4
 .25'06 Rem    120  0.362  2,990  2,382  -1.50   2,252  1,351   -0.2


The downrange performance of these cartridges at 300 yards suggests
that all the XXth century numbers can deliver plenty of wallop for a
satisfactory and ethical kill on deer-sized game but that it's the
Magnums which retain the real power.  In fact, the .300 Weatherby
retains about as much energy at 300 yards as the best of the non-Magnums
manage at their muzzle!  At that range, it's also barely past its
mid-trajectory.  On the other hand, if its 2,818 ftlbs is "overkill,"
the miserable .308 is just as bad at close-in ranges.
     We could add wind drift information and fill in velocity, energy,
and trajectory information for other ranges until space limitations and
attention span become more relevant than practical ballistics.  I
believe, though, that the point is made: Magnums offer an easier route
to long-range performance on game than do transported benchrest
equipment and technique while sub-calibers can, at best, hope to emulate
the performance of older .30 caliber Magnums while ignoring the
capability of sub-caliber Magnums.

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