Gun barrel assembly
A smooth-bore barrel assembly including a first segment that extends downstream of a powder chamber, a bore followed by a segment having an increased diameter, and a final choke constituted by a first final portion and by a second final portion; the barrel is characterized in that the first segment has a divergent-convergent configuration, constituted by a divergent portion and by a convergent portion, or a solely convergent or solely divergent configuration. Advantageously, the barrel assembly can be provided in a modular form and includes three basic components: a barrel body, an extension, an inner choke member and/or an outer choke member.
1. A gun barrel assembly comprising a first segment that extends downstream of a powder chamber, a bore followed by a second segment having an increased diameter, and a final choke constituted by a first final portion and by a second final portion; said first segment having a divergent-convergent configuration, constituted by a divergent portion and by a convergent portion, wherein an internal profile of said barrel is defined by means of a mathematical formula that describes the internal profile along the entire length of said barrel, from said chamber to said muzzle; said formula containing only the diameters and the length of said chamber, defined by chamber parameters (D, H and L) and by additional parameters (ε 0 , ε 1 , β 0 , β 1 , γ 0 , γ 1 , ρ):
f
(
x
)
=
{
D
-
x
L
·
(
D
-
H
)
0
≤
x
≤
L
ε
0
H
(
e
0
-
x
-
L
(
x
2
-
L
)
(
e
0
-
β
1
)
)
L
<
x
≤
x
2
ε
1
H
(
β
1
ε
0
-
x
-
x
2
(
x
3
-
x
2
)
(
β
1
E
0
-
β
0
)
)
x
2
<
x
≤
x
3
(
ε
1
β
0
+
ε
0
β
1
-
ε
0
ε
1
β
1
)
H
x
3
<
x
≤
x
4
(
ε
1
γ
0
+
γ
1
ε
0
-
ε
0
ε
1
γ
1
)
H
x
4
<
x
≤
x
5
(
ε
1
γ
0
+
γ
1
ε
0
-
ε
0
ε
1
γ
1
)
H
-
x
-
x
S
x
6
-
x
S
·
x
5
<
x
≤
x
6
(
(
ε
1
γ
0
+
γ
1
ε
0
-
ε
0
ε
1
γ
1
)
H
-
ρ
(
ε
1
β
0
+
ε
0
β
1
-
ε
0
ε
1
β
1
)
H
)
p
(
ε
1
β
0
+
ε
0
β
1
-
ε
0
ε
1
β
1
)
H
x
6
<
x
≤
x
7
wherein:
D: diameter at chamber mouth;
H: diameter at end of chamber;
L: chamber length;
ε 0 : topological divergence coefficient with a value of “0”;
ε 1 : topological convergence coefficient with a value of “1”;
β 0 : convergence coefficient; the ratio between the bore diameter (d b ) and the diameter at end of chamber (H) (convergent and divergent-convergent case);
β 1 : divergence coefficient; the ratio between the bore diameter (d b ) and the diameter at end of chamber (H) (divergent case); β 1 is greater than β 0 ;
γ 0 : expansion coefficient; the ratio between the diameter of the second segment having an increased diameter (d ob ) and the diameter at end of chamber (H) (convergent and divergent-convergent case);
γ 1 : expansion coefficient; the ratio between the diameter of the second segment having an increased diameter (d ob ) and the diameter at end of chamber (H) (divergent case); γ 1 is greater than γ 0 ;
ρ: choke coefficient; the ratio between the outlet diameter and the bore diameter β 0 or β 1 .
2. The gun barrel assembly according to claim 1 , wherein said second segment having an increased diameter has a constant, divergent or combined configuration.
3. The gun barrel assembly according to claim 1 , wherein the internal profile of said barrel assumes a shape defined by the parameters ε 0 , ε 1 : a profile having a convergent configuration, in which χ 1 =χ 2 .
4. The gun barrel assembly according to claim 1 , comprising the combination of one or more of three basic components: a barrel body, an extension, an inner choke member, an outer choke member.
5. The gun barrel assembly according to claim 1 , wherein said barrel body has a choke provided inside said barrel body; said barrel body having no muzzle thread.
6. The gun barrel assembly according to claim 1 , wherein said barrel body has an internal geometric configuration defined by: a length of the chamber/bore conical blending portion, a bore diameter, and a fixed choke length and type.
7. The gun barrel assembly according to claim 1 , comprising an inner choke member.
8. The gun barrel assembly according to claim 1 , comprising an outer choke member.
9. The gun barrel assembly according to claim 1 , comprising an extension and an inner choke member.
10. The gun barrel assembly according to claim 1 , comprising an extension and an outer choke member.
11. The gun barrel assembly according to claim 1 , having a double configuration, comprising a tube associated with said powder chamber; said powder chamber having a variable length in order to provide different lengths of said gun barrel assembly by using the same tube.
12. The gun barrel assembly according to claim 1 , wherein said formula is valid for all smoothbore calibers.