it does not allow the chamber to be entirely opened until
Generally, in recoil-operated weapons, the barrel
and the bolt move rearward together for a short distance.
the round has left the bore. Action by a recoil spring
returns the bolt to the closed position, chambering anew
Then the barrel is stopped and the bolt (now unlocked)
continues to the rear against spring pressure until the
round.
empty case is ejected. The force of recoil is also used to
Thus, the weight of the breechbolt is an important
cock the weapon and to compress the spring, returning
factor in the design and operation of a blowback-
the bolt to its firing position, and chambering a new
operated weapon. When used with low-powered
round in the process.
ammunition, it is a suitable arrangement. A military
There are two basic methods of recoil operation for
rifle, however, using the standard .30-cal. cartridge and
semiautomatic and automatic small arms. They are the
the blowback action would require a 27-pound
long-recoil (Browning) and short-recoil (Maxim)
breechblock.
methods.
Besides the submachine gun, many types of so-
Long-Recoil Method.--The dynamics of a long-
called pocket automatic pistols and .22-cal. automatic
recoil operation are similar to those in straight
rifles use blowback operations.
blowback operation, except that the barrel,
Range and Rate of Fire
breechblock, and component parts recoil together for
the complete recoil cycle. This recoil distance must be
Every weapon has a certain range (how far the
greater than the length of the complete round. At the
bullet goes) and rate of fire (how fast it fires). The range
end of the recoil stroke, the bolt is held while the barrel
of a weapon is usually indicated in terms of maximum
counterrecoils alone. One important difference in the
range and maximum effective range. The rate of fire of
long-recoil type of operation is that ejection takes place
an automatic weapon is stated as the cyclic rate of fire
on counterrecoil instead of recoil. An example of a
and the sustained rate of fire.
long-recoil weapon is the Browning designed,
MAXIMUM RANGE.--Maximum range is the
Remington model 11 shotgun used by the Navy before
greatest distance that the bullet will travel.
and during World War II.
MAXIMUM EFFECTIVE RANGE.--
Short-Recoil Method.--The dynamics of short-
Maximum effective range is the greatest distance at
recoil-operated weapons approach those of the retarded
which a weapon may be expected to fire accurately to
blowback types more nearly than those of the long-
inflict damage or casualties.
recoil type. To eliminate all blowback tendencies, the
bolt latch is not released until the propellant gases
CYCLIC RATE OF FIRE.--The cyclic rate of
become ineffective. After unlatching (unlocking), the
fire is the maximum rate at which a weapon will fire in
bolt continues recoiling and in some mechanisms is
automatic operation, stated in rounds per minute (rpm).
accelerated by mechanical or gas systems. The barrel is
SUSTAINED RATE OF FIRE.--The sustained
arrested by a spring, a buffer, a stop, or a combination of
rate of fire is normally indicated in a chart that correlates
these and is caused to return by these or the
the average number of rounds fired per minute with the
counterrecoiling components. Examples of short-
number of minutes this rate can be sustained without
recoil-operated weapons are the .45-cal. pistol and the
causing damage to the weapon.
Browning machine gun.
BLOWBACK OPERATION.--There are some
HANDGUNS
similarities between recoil- and blowback-operated
The Navy currently has three types of handguns in
weapons, but there are also several major differences.
its inventory: the M1911A1 .45-caliber semiautomatic
In recoil operation, the bolt and the barrel are locked
pistol; the 9mm, M9 semiautomatic pistol; and the
together until the bullet has left the barrel and most of
the recoil thrust is spent. The combined thrust of the
.38-caliber revolver. We will discuss the operation,
recoiling barrel, bolt, and some other parts is used to
disassembly, and assembly of the .45-caliber and 9mm
operate the weapon. In blowback (inertia) operation,
pistols below.
however, the bolt is not locked to the barrel and in most
M1911A1 .45-CALIBER PISTOL
cases the barrel does not recoil. The bolt is held closed
The .45-cal. M1911A1 pistol (fig. 2-3) is a recoil-
by spring pressure and the mass of the breechblock. The
operated, semiautomatic, magazine-fed, self-loading
initial blow of the exploding cartridge starts the bolt
moving rearward, but the weight of the bolt is such that
handgun with fixed sights. It is often called a .45-cal.
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