 |
|---|
|
Alexey A. Konovalov, member of the Russian Academy of Missiles and Artillery, author of the experimental prototype # 1130. |
|
I remember, back in November of 1996, I had an exclusive opportunity of
being present at the birthday party of an outstanding American gun designer
Gene Stoner, the father of M-16. It was an entirely family gathering of
Stoner's closest friends. Stoner was not feeling well - he just had had a
course of chemotherapy. The only "stranger", along with me, was Gennadiy
Nikonov, designer of the AN-94 assault rifle.
During our conversations, Stoner noted that in the States, the small arms
industry was experiencing serious problems. He went on to say that out of
each 10 University graduates, only one had a qualification of a mechanical
engineer. None of them were specialists in small arms designing.
In response, Gennadiy Nikonov said that, despite the huge problems of the
industry, Universities in St. Petersburg, Tula and Izhevsk were still
providing higher education for future creators of small arms systems. A good
share of MSc and PhD candidates were students of small arms science. Nikonov
at that time was reading up for his PhD dissertation.
For the first time, our Club publishes a first-hand theoretical material.
Member of the Russian Academy of Missiles and Artillery, Alexey A. Konovalov
has recently retired from the Department of Small Arms of the Izhevsk State
Technical University. In his career, Mr. Konovalov, an author of numerous
fundamental researches on small arms, provided training for hundreds of
young engineers. This publication dwells on the novel concepts of small arms
designing.
We hope that "The new principles of building a rotary bolt" will be of
interest for both professionals and amateur gun enthusiasts.
The rotary (sliding) bolt has become popular in the calibers of automatic
small arms as, in addition to its main function of locking the barrel bore
during the shot, the bolt performs a number of other functions:
- accumulator of energy required for performance of automatics;
- it accommodates extractor;
- it performs as a ramming device;
- it holds the next round in the magazine.
Some of these functions can be carried out by the bolt carrier as well.
In order to accumulate enough energy during a shot, with the limitation of
velocity of collision of moving components at hand, the bolt (bolt carrier)
should be heavy. In order to avoid increasing the width of a gun, the bolt
should be long enough. If we could limit the width of the bolt to the
function of holding the next round in a magazine, its section specified as
"À", shall be unnecessary (Fig. 1a).
The bolt needs the amount of travel "À", which serves, on the one hand, to
synchronize in time the motion of the bolt and the feeding the cartridge
into the line of ramming. On the other hand, "À" is required to adjust the
rate of fire. The second factor is predominant in most of the cases. As a
result, the receiver [automatic housing] tends to acquire excessive
dimensions, and makes the entire weapon's system rather extended in terms of
longitudinal sizes. The PPSh - the system taken as classic - has a 270-mm
long barrel. The internal size of the receiver that houses automatics is 350
mm long. Thus, the excessive length of the bolt equals 120 mm, while its
excessive travel (amount of travel of bolt's face behind the cartridge's
head) is 60 mm. By eliminating bolt's excessive length and travel, the
receiver could have been reduced by 180 mm.
The method of reducing the amount of bolt's length is materialized in the
UZI submachine gun by locating the "l" portion of the bolt above the barrel
(Fig. 1b). Such a scheme has become common in such weapon systems as Ingram
and Steyr.
By reducing the amount of bolt's travel over the cartridge head to the level
required for synchronization with feeding, we increase the rate of fire.
This is exactly why most of the modern submachine guns feature the rate of
fire upto 1,200 rpm. It should be noted, however, that the spread of hits in
a burst is optimal if the rate of fire is around 450 rpm.
|
In the following scheme (Fig. 1 c) the travel of bolt over the head of the
cartridge (overrun) can be eliminated at all.
Bolt 1 (bolt carrier) consists of the two parts that are firmly put together
by means of a one-way link. The reverse direction of the link is
spring-loaded (Application # 96112400 (018160), author: A. Konovalov.
Bulletin of Invention # 25 of September 10, 1998).
When the shot is delivered, the case (piston rod of the engine) transfers
pressure onto the bolt (slide). The two components, due to the rigid
linkage, are moving as a single piece. As soon as the bolt covers the amount
of travel sufficient for stripping the next round, the slide is stopped and
retained in this position by spring 3. Further motion is performed only by
the inertia body of bolt 2 (inertia mass). Reaching the point of impact at
the rear side of receiver, the inertia body returns into its initial
position by means of spring 4. On its way back, the bolt follows inertia
body 2. Here, the amount of travel performed by the inertia body is
significantly greater that the amount of travel performed by the bolt in the
two previous cases. This phenomenon reduces the rate of fire. Furthermore,
separation of the bolt recoil impact into two cycles reduces its effect on
the shooter, which helps reduce the spread of hits.
The above scheme makes it possible to reduce overall length of receiver to
the size of two lengths of the cartridge. Further reduction of the size of
receiver is also possible, provided the bolt is free of the function of
holding the round in the magazine. This, however, hardly deems practical as
the construction may become too complicated.
|
For the purpose of proving the above statements, an experimental prototype
of a submachine gun was devised, based on the Makarov PM pistol. Its overall
length and width remained intact, while the height is 20 mm greater. The
overall (empty) weight of the weapon is 1,020 g. The weight of moving parts
is approximately 400 g.
Despite such miniature dimensions, the weapon features the rate of fire of
950 rpm - the factor proves functionality of the elaborated scheme.
Considering that the submachine gun chambered for the PMM (9x18 mm) or
Parabellum (9x19 mm) cartridges should have barrels from 150 to 160 mm long,
we can build an automatic weapon 220 to 230 mm long, featuring the rate of
600 to 700 rpm. In such a weapon, we can use an additional folding (front)
grip or a buttstock similar to the Mauser or Stechkin pistols.
Alexey A. Konovalov,
Academician,
Russian Academy of Missiles and Artillery.
|
|
| Join Guns Banner Exchange |
