U.S. patent application number 10/492991 was filed with the patent office on 2005-02-10 for barrel conversion for a gun.
Invention is credited to Furse, Richard, Saxby, Michael Ernest.
Application Number | 20050028421 10/492991 |
Document ID | / |
Family ID | 9924009 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050028421 |
Kind Code |
A1 |
Saxby, Michael Ernest ; et
al. |
February 10, 2005 |
Barrel conversion for a gun
Abstract
A barrel conversion for a gun comprises; an external, peripheral
surface suitably configured to fit and cycle the gun whose barrel
(1') is to be converted and a stepped internal bore. The stepped
internal bore comprises a first, rifled portion (4') of a first
internal diameter extending from the chamber of the gun, and a
second, clearance portion (3') of a second internal diameter, the
clearance portion (3') extending from the rifled portion (4') to
the exit of the barrel (1'), and the second internal diameter being
larger than the first internal diameter.
Inventors: |
Saxby, Michael Ernest; (East
Sussex, GB) ; Furse, Richard; (London, GB) |
Correspondence
Address: |
LAHIVE & COCKFIELD, LLP.
28 STATE STREET
BOSTON
MA
02109
US
|
Family ID: |
9924009 |
Appl. No.: |
10/492991 |
Filed: |
September 27, 2004 |
PCT Filed: |
October 14, 2002 |
PCT NO: |
PCT/GB02/04657 |
Current U.S.
Class: |
42/77 ;
89/29 |
Current CPC
Class: |
F41A 21/10 20130101 |
Class at
Publication: |
042/077 ;
089/029 |
International
Class: |
F41A 021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2001 |
GB |
0124908.5 |
Claims
1. A barrel conversion device for a gun comprising an external
peripheral surface configured to fit and to cycle the gun whose
barrel is to be converted, and a stepped internal bore, wherein the
stepped internal bore includes a first, rifled portion of a first
internal diameter extending from the chamber of the gun, and a
second, clearance portion of a second internal diameter, the
clearance portion extending from the rifled portion to the exit of
the barrel, and the second internal diameter being larger than the
first internal diameter.
2. The barrel conversion device as claimed in claim 1, wherein the
external peripheral surface comprises an external surface of the
original barrel of the gun to be converted.
3. The barrel conversion device as claimed in claim 1, wherein the
external peripheral surface forms part of a retro-fitted
barrel.
4. The barrel conversion device as claimed in claim 1, wherein the
gun to be converted is a semi-automatic pistol and the rifled bore
portion has a length between about 45 mm and about 80 mm.
5. The barrel conversion device as claimed in claim 4, wherein the
rifled bore portion has a length between about 50 mm and about 75
mm.
6. The barrel conversion device as claimed in claim 4, wherein the
rifled bore portion has a length of about 65 mm.
7. The barrel conversion device as claimed in claim 1, wherein the
rifled bore portion is angled relative to the longitudinal axis of
the barrel.
8. The barrel conversion device as claimed in claim 1, wherein at
least the first rifled portion of the stepped internal bore
comprises a bored liner configured to be inserted into an existing
gun barrel.
9. A gun having a barrel conversion device as claimed in claim
1.
10. (cancelled)
11. (cancelled)
Description
[0001] This invention relates to gun barrels, in particular, but
not strictly limited to pistol barrels, and provides a conversion
for a gun barrel to accommodate shooting of low energy bullets.
[0002] It is known to modify guns originally designed for shooting
live ammunition to enable the shooting of low energy bullets for
training purposes. In the case of automatic pistols, it is known to
replace the entire barrel with a specially adapted barrel having a
bore angled at several degrees to the longitudinal axis of the
barrel in a generally upwards direction when the gun is aimed. The
bore may, simply, be adapted by insertion of a bored liner into the
existing barrel.
[0003] The function of the angled barrel is two-fold. Firstly,
there is a tendency for self loading pistols to move; as the slide
of the automatic weapon moves backwards, the barrel tends to move
downwards. The angle of the bore is designed to compensate for a
loss of accuracy due to the downward movement of the barrel.
Secondly, the angled bore compensates for a relatively slower
trajectory of a low energy (i.e., slower travelling) bullet
relative to live ammunition. Accuracy's of around 200 mm over a
10,000 mm range are achievable with these conversions, independent
of shooter proficiency.
[0004] Whilst the angled barrel conversion goes some way to
improving the accuracy of aim achievable with low energy bullets
(relative to a standard pistol barrel), the correction angle used
to offset the gun's movement as the slide recoils cannot account
for differences in proficiency of a shooter. Also, the arrangement
takes no account of sideways movement of the barrel which is also
known to occur on firing of the gun.
[0005] The present invention aims to provide an improved barrel
conversion which significantly increases the accuracy of the gun
irrespective of shooter proficiency.
[0006] In accordance with the present invention, there is provided
a barrel conversion for a gun comprising; an external, peripheral
surface suitably configured to fit and cycle the gun whose barrel
is to be converted and a stepped internal bore, the stepped
internal bore comprising a first, rifled portion of a first
internal diameter extending from the chamber of the gun, and a
second, clearance portion of a second internal diameter, the
clearance portion extending from the rifled portion to the exit of
the barrel, and the second internal diameter being larger than the
first internal diameter.
[0007] The external peripheral surface may be the external
peripheral surface of the original barrel of the gun to be
converted, or alternatively may be retrofitted. The converted
barrel may have a different length to the original barrel of the
gun to be converted. The rifled portion of the bore is designed
according to conventional practices to accommodate the dimensions
of the bullets to be fired from the converted barrel. The clearance
portion of the bore has a diameter which, as a minimum, is
sufficiently large to permit the bullet to be fired from the
converted barrel to fly unrestricted during involuntary movement of
the gun. Factors to be considered in selecting a suitable diameter
may include, the size, speed and trajectory of the bullet to be
fired and/or the length of the clearance portion, or of the barrel
itself. As with the prior art arrangements, the conversion may be
effected by insertion of a bored liner into the existing barrel.
The bored liner may provide just the rifled portion of the stepped
bore, the internal diameter of the remainder of the original barrel
providing the clearance portion.
[0008] Where the gun to be converted is a semi-automatic pistol,
for most pistols of this type, a rifled bore portion of a length
between about 45 mm to 80 mm has been found to be most effective,
more preferably a length of between about 50 mm to 75 mm. A length
of about 65 mm has been found to provide an accuracy of around a 40
mm diameter in a converted semi-automatic pistol.
[0009] It has been found that, by shortening the rifled portion of
the barrel sufficiently, the flight time of a bullet fired from the
converted gun, in the rifled portion of the barrel can be reduced
to a period which is less than the time taken for any significant
movement of the barrel to result from the firing or cycling of the
weapon. Hence the bullet is in "free flow" when any involuntary
movement of the barrel occurs and it's trajectory is not impaired
or altered by such movement.
[0010] Optionally, the rifled bore portion of the barrel may be
angled to the longitudinal axis of the barrel to compensate for the
trajectory of slower bullets.
[0011] An embodiment of the invention will now be further described
by way of example, with reference to the figures in which:
[0012] FIG. 1 shows a prior art arrangement of a converted barrel
of a pistol.
[0013] FIG. 2 shows an embodiment of a barrel conversion according
to the invention for a pistol similar to that referred to in
relation to FIG. 1.
[0014] As can be seen from FIG. 1 a gun barrel 1 of known
construction is modified for firing low energy training ammunition
by the provision of a liner 2, within the bore 3 of the original
barrel 1 of the gun (not shown) to be modified. The liner 2 extends
the full length of the bore 3 of the barrel 1.
[0015] The liner 2 has its own longitudinal bore 4 which extends
the length of the liner 2. The longitudinal bore 4 has an axis B'
which is angled to the longitudinal axis A of the barrel 1 in a
generally upwardly direction when the gun (not shown) is aimed for
shooting the training ammunition. The angle is typically about 6 to
8 degrees from the longitudinal axis A of the barrel 1.
[0016] As can be seen in FIG. 2, a gun barrel 1' similar to that
shown in FIG. 1 is modified in accordance with one embodiment of
the present invention. Inside the barrel 1', there is inserted a
liner 2'. The liner 2' is significantly shorter in length than the
bore 3' of the barrel 1', the liner 2' being approximately 55-60%
of the length of the bore 3'. The liner 2' has a longitudinal bore
4' with an axis B' which, optionally, is angled to the longitudinal
axis A' of the barrel 1' in a generally upwardly direction when the
gun (not shown) is aimed for shooting the training ammunition.
* * * * *