Ordnance – Automatic – Movable barrel
Reexamination Certificate
1999-10-26
2001-11-20
Johnson, Stephen M. (Department: 3641)
Ordnance
Automatic
Movable barrel
C089S187010
Reexamination Certificate
active
06318231
ABSTRACT:
TECHNICAL FIELD AND BACKGROUND OF THE INVENTION
This invention relates to firearms and more particularly to semi-automatic, or autoloading pistols. This application discloses a precision barrel muzzle bushing and a method of producing the bushing.
A very popular model of semi-automatic pistol is the U.S. caliber .45 model 1911 pistol as made by Colt, Remington, Ithaca Gun Company and others with an estimated several million having been made from 1911 to date. Other autoloading pistols of generally similar design are the Browning Model P35, the Smith and Wesson Model 39, the Polish Radom and the Russian M1933 Tokarev. In general, the invention has application to any semi-automatic 45, 40 or 38 caliber pistol, as well as 9 and 10 mm pistols, such as the 9 mm Beretta currently used by the United States and some other NATO armed forces, in which the barrel is moved into a battery, or lock-up, position by means of a lug link or camming surface.
In all of these pistols the barrel and slide are separate parts with the barrel unlocking itself from the slide, which includes the bolt, as the slide moves to the rear in response to at firing. This design inherently causes a heavy recoil and firing inaccuracy because the barrel and sights are not integral. Moreover, because many of these weapons are made to be used in combat circumstances where fouling by dirt, grease and other contaminants may occur without the opportunity for frequent cleaning, tolerances between critical operating parts such as the shell ejection opening and barrel hood, the barrel and receiver housing, and the barrel and slide locking grooves are deliberately greater than necessary to achieve optimum firing accuracy and reliability in order to permit operation even when fouled, and to permit easy field disassembly and repair.
A standard 45 caliber Colt when properly adjusted with no worn or damaged parts when bench fired will hit a target at 50 feet with a spread of approximately 6 inches (15 cm). The barrel of such a handgun is actually permitted to move a few thousandths of an inch during firing and is not held rigid. A few thousandths of an inch movement of the barrel easily results in a several inch variation in movement of the projectile at fifty feet. This means that only chance will result in a firing pattern significantly tighter than 6 inches (15 cm). Manufacturing variations between components of various manufacturers and rebuilders also introduce a further degree of inaccuracy into the operation of the pistol.
The continuing popularity and availability of these pistols has resulted in their use for sport target competition, and as weapons for special military and police units where enhanced accuracy is necessary or desirable. This invention provides a novel barrel muzzle bushing which permits proper movement of the barrel into and out of lockup, while providing enhanced accuracy and protection to the barrel against damage.
SUMMARY OF THE INVENTION
Therefore, it is an object of the invention to provide a barrel bushing for semi-automatic pistols which enhances the accuracy of the pistol.
It is another object of the invention to provide a barrel bushing for semi-automatic pistols which reduces wear to the moving parts of the pistol.
It is another object of the invention to provide a barrel bushing for semi-automatic pistols which reduces the possibility of damage to the pistol.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a barrel bushing for a semi-automatic pistol. The barrel bushing defines a bore for receiving a barrel therein for reciprocating movement during operation of the pistol. The improvement to the barrel bushing comprises first, second and third annular bearing surfaces formed on inner walls of the bore and against which the barrel moves dining operation of the pistol. The first bearing surface contacts and supports the barrel during the recoil phase of operation, and defines a plane parallel to the longitudinal axis of the barrel during recoil. The second and third bearing surfaces reside in axially spaced-apart relation on opposite axially-extending sides of the first bearing surface and define respective planes with respect to the first bearing surface which are parallel to the longitudinal axis of the barrel during lockup and on which opposite upper and lower surfaces of the barrel are supported during lockup.
According to one preferred embodiment of the invention, the first bearing surface defines an axial length which is 22 percent the length of each of the second and third bearing surfaces.
According to another preferred embodiment of the invention, the second and third bearing surfaces each reside at an angle of 0°52′ with reference to the first bearing surface.
According to yet another preferred embodiment of the invention, the invention comprises a semi-automatic pistol in combination with a barrel bushing as claimed and described herein.
Preferably, the pistol comprises a Colt 45 caliber semi-automatic pistol.
An embodiment of the method of manufacturing a barrel bushing according to the invention comprises the steps of forming a first bearing surface contacting and supporting the barrel during the recoil phase of operation, the first bearing surface defining a plane parallel to) the longitudinal axis of the barrel during recoil, and forming a second and third bearing surfaces in axially spaced-apart relation on opposite axially-extending sides of the first bearing surface, and defining respective planes which are parallel to the longitudinal axis of the barrel during lockup and on which opposite upper and lower surfaces of the barrel are supported during lockup.
REFERENCES:
patent: 5076139 (1991-12-01), Hiett
patent: 5501135 (1996-03-01), Beretta
patent: 5952602 (1999-09-01), Beretta
patent: 673028 (1952-05-01), None
Adams, Schwartz & Evans P.A.
Johnson Stephen M.
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