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Shooting the 6.5 X 52 mm, 7.35 x 51mm Cartridges and the Carcano Rifles,
an article by Dave Emary, Senior Ballistician of Hornady Manufacturing
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The 6.5 X 52 mm cartridge has taken a great deal of criticism as being
underpowered and anemic. From a ballistic standpoint this is a little hard
to justify. The Swedish 6.5 X 55 mm cartridge is considered an outstanding
cartridge yet it is only able to produce 100 fps more velocity with a
156-grain bullet in the M96 rifle. The 6.5 X 55 requires a maximum average
pressure of 55,000 psi and approximately 6 more grains of powder to
produce this meager gain in performance. The . 30-30 Winchester, regarded
as an adequate deer rifle and known to have killed many moose and bear
produces 2,220 fps in a 24” barrel with a 170 grain bullet. The 6.5 X 52
mm fires a bullet with a higher ballistic coefficient, at a higher
velocity, shoots flatter and has far more penetration capability than the
.30-30. From the standpoint of a service rifle cartridge the 6.5 X 52 with
its relatively low operating pressure, coupled with its modest powder
charge would result in much less barrel throat erosion and wear. This
would equate to longer barrel life and decreased operating cost. In fact,
much of what was done in the Carcano rifle/ammunition system was aimed at
long barrel life, as will be shown later. From my point of view the 6.5 X
52 is a very efficient cartridge, offering adequate performance for what
it was intended.
The only fault that one might level against the 6.5 X 52 as a military
cartridge is that it had relatively humane terminal ballistics. The very
long, blunt nosed bullet coupled with the fast twist rate of the gun
resulted in a bullet that was very stable with a very high resistance to
tumbling. The cartridge was known to have inflicted many “through and
through” wounds, just leaving a small wound channel. The bullet
typically would not tumble inside its’ target unless it encountered
something hard such as bone. When it did tumble the wounding effect is
well known.
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The original 6.5 X 52 mm Carcano design used a gain twist barrel. The gain
twist results in a very slow initial twist in the barrel progressively
getting faster until the full twist rate is attained at the muzzle. The
slow initial twist results in substantially less torque being imparted to
the bullet during the highest loading phase of the interior ballistic
cycle. This results in significantly less barrel wear in the throat. This
coupled with the very deep rifling of the barrel would result in barrels
that would have a very long wear and accuracy life. This in fact is the
case. Many M91 model rifles show signs of considerable amounts of
ammunition being fired through them, because of the crazed/frosted
condition of the bore, yet still show very strong rifling and shoot well
with the proper size bullets. The 7.35 X 51 mm Carcano rifles used a
standard fixed twist barrel. The Carcano bolt is the model of a simple,
easy to field strip bolt. It is about as fool proof as you can get for a
common soldier. The Carcano trigger has taken a considerable amount of
criticism. The trigger is basically a Mauser type two-stage trigger. In
almost all cases if you find the trigger rough or creepy simply polishing
the sear and trigger mating faces result in a very acceptable trigger for
a military rifle. For the most part I have found Carcano triggers have
less creep, are more crisp and lighter than the majority of Mauser
triggers I have encountered.
The materials used in the Carcano are excellent. These rifles were made
from special steels perfected by the Czechs, for which the Italians paid
royalties. If you have ever tried doing any work on a Carcano receiver you
will find out just how hard and tough the steel is. The Carcano has also
received a reputation as being a “weak” design. Nothing could be
further from the truth. The Italians made a small run of Carcanos early in
WW II chambered for 8 X 57 JS. The Germans rechambered some Carcanos to 8
X 57 JS late in WW II. These rifles were also proofed for this cartridge.
The CIP minimum suggested proof pressure for the 8 x 57 JS cartridge is
73,500 psi. I hardly call this a weak action.
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The Italians apparently realized that a 300-meter battle zero was a bit
impractical and with the introduction of the M38 models went to a 200
meter battle zero. This zero results in a maximum height of trajectory of
5.5” – 6.5” at a range of approximately 100 yards, depending on
barrel length. With this sight setting, by simply holding on the middle of
the torso, it would have been hard to miss the target out to about 220
meters. The Carcano’s also used a unique sight picture. The proper sight
picture for regulated sights on a Carcano is with the front sight in the
very bottom of the rear sight groove. This is how the Italian army manuals
instructed that the sights be used. Potentially, this would allow for two
battle sight settings. The normal use as mentioned above would be a 200
meter zero. Using the Mauser sighting method, the front sight level with
the rear sight, would result in a zero of 330 – 350 meters. This is
about the maximum range practical for attempting to engage a target with
iron sights. I contend with the Carcano the Italians had a very
intelligent approach for a battle rifle. The fixed sights were basically
fool proof. The Italians must have realized with the M38 models that
nearly all small arms engagements occurred inside of 200 meters. The fixed
sights with a 200 meter zero would have been fool proof for a soldier
under stress, who was probably a poor judge of distance to begin with. The
soldier would have had to do nothing but point and shoot at the middle of
his enemy for ranges out to 220 – 230 meters. How much more simple and
effective could it have been made.
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6.5 x 52 mm
The Carcano rifles are capable of outstanding accuracy. With the exception
of a military issue type load in the short carbines they are very pleasant
to shoot from a recoil standpoint. Because of the above mentioned sight
picture for the Carcano, front sight in the bottom of the rear sight
notch, it is very important to have a consistent stock- cheek weld for
consistent accuracy. It is often very helpful to use a carbide lamp or a
sight black product to blacken the sights, which improves contrast and
sight picture.
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CONCLUSION:
The 6.5 X 52 is a very useful and capable cartridge. It served well as a
military cartridge for over 80 years. The 7.35 X 51 would have been an
even more effective military cartridge than the 6.5 X 52 had its timing
been different. It is interesting to note that the .308 Winchester / 7.62
X 51 mm NATO and the 7.35 X 51 mm are nearly the same dimensions. Both the
6.5 and 7.35 cartridges are fun to shoot and properly loaded capable of
very good accuracy. The Carcano rifle is a well made rifle that is by no
means weak or poorly manufactured. They are reliable and strong rifles
that are fun to shoot and offer a tremendous variety of types and markings
for the collector. I will admit that they are a rather utilitarian rifle
as compared to some others. However, they are probably one of the most
efficient, cost effective, user friendly battle rifles produced in their
era. The rifle, ammunition combination properly loaded is capable of
accuracy that will rival the most accurate of the Mauser chamberings.
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Carcano Homepage: Italian Military Rifles and Carbines
http://personal.stevens.edu/~gliberat/carcano/
