U.S. patent number 3,657,959 [Application Number 04/849,977] was granted by the patent office on 1972-04-25 for automatic pistol and sub-caliber conversion therefor.
Invention is credited to Frederick H. Kart.
United States Patent |
3,657,959 |
Kart |
April 25, 1972 |
AUTOMATIC PISTOL AND SUB-CALIBER CONVERSION THEREFOR
Abstract
The invention provides a conversion means for converting a large
caliber automatic pistol to an accurate sub-caliber automatic
pistol without making any exterior changes in the large caliber
pistol. In the prior art the well-known Colt automatic pistol,
caliber .45, Government model, can be converted to a sub-caliber
automatic pistol by means of a conversion kit which includes a
different slide, a different barrel, a different recoil spring, a
different slide-stop, and a series of spacers to surround the
recoil spring guide to shorten the recoil movement. To improve the
accuracy of such converter large caliber automatic pistol the
present invention makes the following changes in certain of the
conversion parts. The smaller caliber barrel is provided at its
rearward end with aligned cheeks for engagement with the upper
surface of the receiver; a flattened surface is provided on one
lateral face of such smaller caliber barrel including one of said
cheeks to facilitate insertion of such barrel within the pistol
slide; an elongated hole inclined upwardly at an angle of
45.degree. is provided in the barrel extension member which
receives the slide-stop pin; a screw-threaded hole is provided in
the front face of the barrel extension member for receiving a
barrel locking screw which extends through the recoil spring guide;
the barrel locking screw engages the front end of the recoil spring
guide and upon tightening of said screw brings the barrel cheeks
and upper surface of the receiver into firm engagement; and the
slide stop is provided with a relatively movable bar and pin.
Inventors: |
Kart; Frederick H. (Riverhead,
NY) |
Family
ID: |
25306961 |
Appl.
No.: |
04/849,977 |
Filed: |
August 14, 1969 |
Current U.S.
Class: |
89/128;
89/196 |
Current CPC
Class: |
F41A
11/02 (20130101); F41A 21/10 (20130101) |
Current International
Class: |
F41A
11/00 (20060101); F41A 21/10 (20060101); F41A
21/00 (20060101); F41A 11/02 (20060101); F41d
011/06 () |
Field of
Search: |
;89/29,128,163,196
;42/77 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Bentley; Stephen C.
Claims
What I claim is:
1. An automatic pistol having a receiver, a slide, a barrel for
recoiling movement relative to said receiver and slide, spring
means yieldingly resisting said recoiling movement, said receiver
and slide having interfitting grooves and flanges, said receiver
having an upper surface above said interfitting grooves and flanges
on each side of said barrel which parallels the axis of said
barrel, and conversion means for converting said pistol from a
large caliber bore to a smaller caliber bore, characterized in that
said conversion means comprise
a. a small caliber bore barrel having on each exterior side wall
adjacent its rearward end a cheek extending forwardly from said
rearward end, parallel to the axis of said barrel, each cheek
having a lower surface adapted for engagement with one of said
upper surfaces of said receiver, and
b. means for firmly engaging said cheeks and the upper surfaces of
said receiver at all times.
2. An automatic pistol according to claim 1, wherein said small
caliber bore barrel has one of its lateral faces including one of
said cheeks flattened so as to permit said small caliber bore
barrel to be inserted in the slide from its underside.
3. An automatic pistol according to claim 1, in which the barrel
has a downwardly projecting extension member, a recoil spring
guide, a coil spring surrounding said guide, and a plurality of
spacers surrounding said spring guide adjacent said extension
member and serving to limit the recoil movement of the slide to
accommodate to a smaller caliber bullet, further characterized in
that said conversion means also comprise
c. a screwthreaded hole in the front face of said barrel extension
member,
d. a barrel locking screw disposed within said spring guide and
having a head engaging the front end of said spring guide, said
screw being in threaded engagement with the hole in the front face
of said barrel extension member, and
e. a slide-stop pin disposed in an elongated, upwardly-inclined
slot in said barrel extension member,
whereby upon tightening of said barrel locking screw the cheeks on
the conversion barrel are forced into firm engagement with the
upper surface of the receiver.
4. An automatic pistol according to claim 3, wherein
f. the elongated, upwardly-inclined slot is disposed at an angle of
approximately 45.degree. to the longitudinal axis of the barrel,
and
g. the slide-stop has a relatively movable bar and pin with the pin
mounted in the elongated, upwardly-inclined slot.
5. An automatic pistol according to claim 4, wherein the slide-stop
comprises a pin member with a reduced end having a screwthreaded
hole therein, a bar having a bearing hole at one end for receiving
the reduced end of the pin, and a screw for engagement through the
hole in the bar with the screwthreaded hole in the pin, whereby
relative movement between the pin and bar is permitted.
Description
This invention relates to automatic pistols. More particularly it
provides improved means for converting automatic pistols of large
caliber to sub-caliber while maintaining the accuracy of the
pistol.
The Colt automatic pistol, caliber .45, Government model, is well
known in the art and has been extensively used as a service
pistol.
It has been proposed in the past to convert such Colt .45 caliber
automatic pistol to a sub-caliber pistol, such for instance as a
.22 caliber pistol, by the use of a conversion kit which included
various parts to be substituted for parts of the .45 caliber pistol
in order to convert it to a .22 caliber pistol. One such conversion
kit as offered for sale by the manufacturer of the Colt .45 caliber
pistol includes a different slide, a different barrel, a different
recoil spring, a different slide-stop, and a series of spacers to
surround the recoil spring guide to shorten the recoil
movement.
In converting a .45 caliber piston to a .22 caliber pistol, it is
of course highly desirable that the changes made in the .45 caliber
pistol not be permanent. On the contrary, it is highly desirable
that the .22 caliber conversion be readily restorable to its
original condition as a .45 caliber pistol.
Furthermore, in competitive target shooting, such as in "hard ball"
matches, it is a basic requirement that there shall have been no
exterior changes in the .45 caliber pistol.
I have found that with prior art conversion kits in changing a .45
caliber pistol to a sub-caliber pistol such as a .22 caliber
pistol, it has not been possible to attain a high degree of
accuracy with such sub-caliber pistol. Hence, up until now, in
order to attain the desired accuracy with a .45 caliber pistol,
when converting it to a .22 caliber pistol, it has been a common
practice to utilize, on an individual basis, the services of a
skilled gunsmith who would carefully adjust and modify the various
tolerances so as to impart as much accuracy as possible to such
converted pistol. After such conversion, however, it was not
possible to restore the pistol to its original .45 caliber
condition.
It is an object of the present invention to provide apparatus for
converting a .45 caliber pistol to a sub-caliber pistol such as a
.22 caliber without modifying the exterior appearance of such
pistol; to permit such pistol to be returned very quickly to its
original .45 caliber condition; and to impart to such .22
conversion a high degree of accuracy such that it is at least as
accurate, if not more accurate than a .45 caliber pistol which has
been modified individually by a gunsmith for use in competitive
target shooting.
In accomplishing the foregoing objects I start with a .45 caliber
Colt pistol which has been modified with the manufacturer's
conversion kit to a .22 caliber pistol. I then modify the .22
caliber pistol which results from such conversion by providing on
the substitute .22 caliber barrel at its rearward end two
longitudinally-disposed aligned cheeks which are brought into firm
engagement with the upper surface of the pistol receiver, and
thereby assure pistol accuracy independently of the tolerances
between the slide and receiver. I also provide on one of the
lateral faces of the conversion barrel a flat portion which permits
such modified conversion barrel to be inserted in the slide from
the bottom.
In addition, I also provide an upwardly inclined elongated
slide-stop hole in the downwardly projecting extension member on
the barrel and also provide a tapped or screwthreaded hole in the
front end of such extension member which is in alignment with the
recoil spring guide, such screwthreaded hole being in communication
with the upwardly-inclined, elongated slide-stop hole, and a barrel
locking screw extending through such recoil spring guide and into
such screwthreaded hole in the front end of the barrel member with
the head of said screw bearing against the recoil spring guide,
which in turn bears against the receiver, whereby upon tightening
of the screw the barrel is pulled forwardly, the slide-stop pin
rides upwardly along the elongated slide-stop hole, the barrel is
forced downwardly, and the aligning cheeks are brought into firm
contact with the receiver. I have also provided an improved
slide-stop which permits the slide-stop bar to turn on the pin.
For a more detailed understanding of the invention reference will
now be made to the accompanying drawings wherein:
FIG. 1 is a side elevation, partially fragmentary and partially
broken away to show underlying structure, of the prior art Colt .45
caliber automatic pistol, Government model, converted by the
well-known conversion kit to a .22 caliber automatic pistol.
FIG. 2 is a fragmentary perspective view of the slide-stop for such
prior art .45 caliber Colt, Government model, pistol, converted to
a .22 caliber pistol.
FIG. 3 is a view similar to FIG. 1 but showing a .45 caliber Colt
pistol converted according to the prior art to a .22 caliber pistol
and then further modified according to the present invention.
FIG. 4 is a view similar to FIG. 2 but showing the slide-stop as
modified according to the present invention.
FIG. 5 is a sectional view taken on the line 5--5 of FIG. 1 looking
in the direction of the arrows and showing the slide, barrel,
receiver and slide-stop of the prior art Colt .45, Government
model, pistol, converted according to the prior art to a .22
caliber pistol.
FIG. 6 is a view similar to FIG. 5 but showing the modified barrel,
slide-stop, and barrel locking screw provided by the present
invention.
FIG. 7 is an enlarged fragmentary view in side elevation similar to
FIG. 3, showing one side of the barrel as modified according to the
present invention.
FIG. 8 is an end elevational view of the barrel viewed from the
right of FIG. 7.
It will be noted that for clarity of disclosure and ready
reference, FIGS. 1, 2 and 5 carry the legend "Prior Art" in
parentheses.
Referring now to the drawings for a more complete understanding of
the improvements made by the present invention, it will first be
noted from FIG. 1 of the drawings, which illustrates the well-known
Colt automatic pistol, caliber .45, Government model, converted
according to the prior art to a .22 caliber pistol, that such
pistol includes the basic elements of: A receiver 10 having a grip
portion 11, a trigger 12, a safety 13, a recoil spring guide 14,
spacers 14a surrounding said spring guide, a recoil spring 15
surrounding such guide and engaging said spacers, barrel 16 from
which the bullet is ejected, and a slide 17 disposed over such
barrel and in sliding engagement with the receiver. Such prior art
converted Colt pistol also includes a slide-stop 20, such as shown
in perspective in FIG. 2 of the drawings, including a bar 21 and a
pin 22 rigidly connected thereto. The pin 22 of the slide-stop is
also shown in cross-section in FIG. 1.
With the converted pistol of the prior art, for accuracy of firing
it has been necessary to maintain very close and accurate
tolerances between the barrel 16, the slide 17 and the receiver 10.
Thus, as best seen in FIG. 5 of the drawings, which is a sectional
view taken along the lines 5--5 of FIG. 1, the .22 caliber Colt
conversion slide has longitudinal grooves 23 which are interfitted
with and engaged by longitudinal flanges 24 on the Colt .45 caliber
receiver, and that such slide also has longitudinal flanges 25
which are interfitted with and engaged by longitudinal grooves 26
on the receiver. Such interfitted grooves and flanges must be
accurately machined to provide the maximum of pistol accuracy.
It will thus be understood as shown in FIG. 5 of the drawings that
the accuracy of a Colt .45 and its conversion .22 caliber pistol is
dependent upon the closeness of tolerances between the barrel and
the slide and the tolerances between the flanges and grooves in the
slide and receiver.
It will also be noted in FIG. 2 of the drawings that in the prior
art Colt conversion pistol the slide-stop 20 has the pin 22 rigidly
secured to the bar 21.
In modifying a conversion pistol of the type shown in FIG. 1 to a
.22 caliber pistol according to the present invention, a .22
caliber barrel 27 is substituted for the barrel 16. This barrel is
illustrated in FIGS. 3, 6, 7 and 8 of the drawings. It will first
be noted from FIG. 6 that such barrel has been provided on one side
with a flat surface 28 which permits the barrel to be inserted
through the bottom of the slide 17'. The receiver 10 is the same as
the receiver shown in FIGS. 1 and 5 and has not been changed or
altered.
The barrel 27 has been provided on each side with cheeks 30, 30a at
the rear of the barrel and which are integral therewith, such
cheeks being accurately ground to provide guiding edges 31 which
bear against and firmly engage the upper surfaces 32 of the
receiver 10. With this construction it will be noted that the
accuracy of the pistol is no longer dependent upon the tolerances
between flanges and grooves on the slide 17' and the receiver 10;
but instead the accuracy is directly controlled by the engagement
of the cheeks 30 on the barrel 27 with the upper surfaces 32 of the
receiver. In practice it has been found that such cheeks preferably
have a longitudinal dimension along the barrel of approximately 1
inch.
The second change or alteration made by the present invention is
that a hole is provided in the front face of barrel extension
member 35, such hole being marked 36. The hole 36 is in axial
alignment with the spring guide 14. A barrel locking screw 37 is
inserted within the spring guide and engages screwthreadedly in the
hole 36 in barrel extension member 35.
As with the prior art conversion, a plurality of spacers 40
surround the spring guide and shorten the effective length of the
recoil spring, the end coil of the spring 15' engaging the exposed
face of the outermost spacer, -- the spacers usually being about
three-sixteenths inch thick. I have found that five or six of such
spacers provide the proper timing for firing a .22 caliber
cartridge while permitting the slide to work in a long enough
stroke that the disconnector and other parts function in proper
sequence. Generally speaking, the prime purpose of the spacers is
to correct the timing for a .22 caliber bullet as against a .45
caliber bullet.
A further change which is made by the present invention is that the
hole 41 for the pin 22 of the slide-stop 20 in the pistol of FIG. 1
has been elongated along a 45.degree. axis to provide hole 41' as
best seen in FIG. 7. It will also be noted, as best seen in FIG. 4,
that the slide stop 45 of the present invention as shown in
exploded view in FIG. 4, does not have its pin and bar integral or
rigid one with the other, but on the contrary a through hole 46 is
provided in the bar 47 for receiving a reduced end connection 48
for the pin 49. A screw 50 for engagement in the internally
screwthreaded end 48 holds the pin and bar in assembled relation
while permitting such bar and pin to pivot or rotate relatively to
each other.
By reference to FIG. 3, it will be noted that the barrel locking
screw 37 bears against the front end of the recoil spring guide 14,
and is engaged in the screwthreaded hole 36 in the front end of the
barrel extension member 35, a clearance 51 being provided. The
opposite end of the spring guide, in turn, bears against the
receiver 10. Upon tightening of the screw 37 the barrel 27 is
pulled forwardly, the slide-stop pin 49 is caused to ride upwardly
along the elongated slide-stop hole 41', the barrel 27 is forced
downwardly and the aligning cheeks 30, 30a are brought into firm
contact with the upper surface 32 of the receiver 10. In this way
the cheeks on the barrel of the .22 caliber pistol align directly
with the upper surface of the receiver and it is not necessary to
rely upon the tolerances between the receiver and slide for
accuracy.
From the foregoing description it will be understood that I have
provided improved means for converting a .45 caliber pistol to a
.22 caliber pistol without making any permanent changes in such .45
caliber pistol and without any exterior changes which would prevent
such pistol from being used in competitive "hard ball" matches. It
will also be apparent that the .22 conversion can be readily
reconstituted as a .45 caliber pistol.
It will thus be apparent that an owner of a .45 caliber pistol who
is interested in competitive target shooting can readily change
such a pistol into an accurate .22 caliber target pistol merely by
following the teachings of the present invention.
* * * * *