M4A1 helically fluted barrel

Abstract

An M4A1 helically fluted gun barrel is provided which increases sustained peak temperature levels for the barrel. This M4A1 helically fluted gun barrel incorporates multi-start variable pitch helical openings into the exterior profile of a standard M4A1 heavy barrel. The helical openings increase the outer surface area for heat dissipation, and also reduce weight as a further advantage.

Claims

1. An improvement to a M4A1 weapon's Heavy Barrel wherein said Heavy Barrel's exterior surface (FIG. 6) then has certain specific openings (FIG. 2) made thereon for enhancing the Heavy Barrel's heat dissipation capacity, being: helically fluted openings on the exterior surface of the said Heavy Barrel, and, with all distances as measured from the muzzle end of the said Heavy Barrel, said helically fluted openings comprising: a first set of openings (Section A) beginning at a start distance SDA=1.27 inches from the muzzle end and continuing through until an end distance EDA=2.85 inches from the muzzle end, being flat top helically fluted identical openings, advancing in clockwise fashion, at identical pitch P=1.2, and having fin spacing S=0.14 inches therein between, and having fin length L=0.15 inches, and having fin depth D=0.15 inches on all the openings thereof, and having identical cross sectional shapes on all the openings within said first set of openings, and; a second set of openings (Section B) beginning at a start distance SDB=3.87 inches from the muzzle end and continuing through until an end distance EDB=5.24 inches from the muzzle end, being flat top helically fluted identical openings, advancing in clockwise fashion, at identical pitch P=1.2, and having fin spacing S=0.13 inches therein between, and having fin length L=0.15 inches, and having fin depth D=0.15 inches on all the openings thereof, and having identical cross sectional shapes on all the openings within said second set of openings, and; a third set of openings (Section C) beginning at a start distance SDC=7.15 inches from the muzzle end and continuing through until an end distance EDC=12.37 inches from the muzzle end, being flat top helically fluted identical openings, advancing in clockwise fashion, at identical pitch P=0.74, and having fin spacing S=0.14 inches therein between, and having fin length L=0.045 inches, and having fin depth D=0.15 inches, tapering down to 0.05 inches on the openings thereof, and having identical cross sectional shapes on all the openings within said third set of openings.

2. The improvement to the M4A1 weapon's Heavy Barrel of claim 1, wherein the openings (FIG. 2) are grooves.

3. The improvement to the M4A1 weapon's Heavy Barrel of claim 1, wherein the openings (FIG. 2) are cut as threads.

Description

LIST OF DRAWINGS

(1) FIG. 1 is a right side looking isometric view (from the muzzle end) of an M4A1 Helically Fluted Gun Barrel according to this invention, and;

(2) FIG. 2 is a front elevation view of an M4A1 Helically Fluted Gun Barrel in accordance with this invention, showing start and end dimensions of three sections of the barrel (A, B, and C) where openings may be present in accordance with this invention, and;

(3) FIG. 3 is a right side elevation view (muzzle end) of an M4A1 Helically Fluted Gun Barrel M4A1 according to this invention, and;

(4) FIG. 4 is a left side elevation view (breech end) of an M4A1 Helically Fluted Gun Barrel according to this invention, and;

(5) FIG. 5 provides a sketch to explain depth, spacing, and width, e.g., of openings which may be provided in the barrel exterior, and;

(6) FIG. 6 shows outside view of one standard M4A1 rifle, heavy gun barrel.

DETAILED DESCRIPTION

(7) FIG. 1 shows a right side looking isometric view (from the muzzle end) of an M4A1 Helically Fluted Gun Barrel according to this invention. It has three different sections (A, B, and C) in which there are openings in accordance with this invention; the location of these three sections are given in FIG. 2. The openings shown there may be formed of 4-start screw threads.

(8) The first set of openings (Section A) begin at a start distance SDA from the muzzle end and continue through until an end distance EDA from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PA, and have fin spacing SA therein between, have fin length LA, and have fin depth DA on all the openings thereof, and have identical cross sectional shapes on all the openings within said first set of openings.

(9) The second set of openings (Section B) begin at a start distance SDB from the muzzle end and continue through until an end distance EDB from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PB, and have fin spacing SB therein between, have fin length LB, and have fin depth DB on all the openings thereof, and have identical cross sectional shapes on all the openings within said second set of openings.

(10) The third set of openings (Section C) begin at a start distance SDC from the muzzle end and continue through until an end distance EDC from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PC, and have fin spacing SC therein between, have fin length LC, and have fin depth DC. The fin depth gradually tapers down on the openings thereof all the way along until the end of Section C. The openings in Section C all have analogously similar cross sectional shapes within the said third set of openings.

(11) The fin thickness and spacing between adjacent turns of the helix are selected for efficient removing of heat; some of the considerations include the following. A thicker fin increases the stiffness of the barrel for strength. More spacing allows better escape of heat but more turns per inch can dissipate much more heat than fewer. Too many turns per inch makes a sharp surface that may be hard to grip for barrel removal and replacement. Depth of the openings cannot be made too great lest the remaining wall thickness of the barrel in places becomes too thin for the barrel to hold the pressures within it during firing. This invention of a multi-start helically fluted barrel may also be used on weapons other than the M4A1. The benefits could include higher cook-off limit, increased sustained rate of fire, increased stiffness which reduces barrel deflection yielding better accuracy, reduced erosion, and reduced weight.

(12) The following describes one successful embodiment of the invention.

(13) The first set of openings (Section A) begin at a start distance SDA=1.27 inches from the muzzle end and continue through until an end distance EDA=2.85 inches from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PA=1.2, and have fin spacing SA=0.14 inches therein between, and have fin length LA=0.15 inches, and have fin depth DA=0.15 inches on all the openings thereof, and have identical cross sectional shapes on all the openings within said first set of openings.

(14) The second set of openings (Section B) begin at a start distance SDB=3.87 inches from the muzzle end and continue through until an end distance EDB=5.24 inches from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PB=1.2, and have fin spacing SB=0.13 inches therein between, and have fin length LB=0.15 inches, and have fin depth DB=0.15 inches on all the openings thereof, and have identical cross sectional shapes on all the openings within said second set of openings.

(15) The third set of openings (Section C) begin at a start distance SDC=7.15 inches from the muzzle end and continue through until an end distance EDC=12.37 inches from the muzzle end, being flat top helically fluted identical openings, advance in clockwise fashion, at identical pitch PC=0/4, and have fin spacing SC=0.14 inches therein between, and have fin length LC=0.045 inches, and have fin depth DC. The fin depth DC starts at being=0.15 inches, and gradually tapers all along Section C until it reaches down to 0.05 inches on the openings thereof at the end of Section C. The openings in Section C all have analogously similar cross sectional shapes within the said third set of openings.

(16) While the openings in sections A, B, and C were described as being 4-start threading, they might also be multi-start, i.e., in multiples other than four. The pitch P of these threads may also be made variable, either within a given set of openings or variable as between different sets of openings. It is noted that the openings extend substantially along the length of the barrel, and may cover more than half of the exterior surface of the barrel. It will be appreciated that the openings result in: reduced barrel weight; improved heat dissipation; improved cook-off resistance; increased sustained rate of firing; optimized dispersion performance, and reduced bore erosion which results in increased barrel life.

(17) FIG. 3 shows a right side elevation view (muzzle end) of an M4A1 Helically Fluted Gun Barrel M4A1 according to this invention, and FIG. 4 shows a left side view (breech end) thereof. FIG. 5 provides a sketch to illustrate depth D, spacing S, width L, small radius R1, large radius R2, of the openings provided in the barrel exterior according to this invention. FIG. 6 shows the exterior of a standard M4A1 rifle, heavy gun barrel (no openings). Several prototype M4A1 helically fluted barrels of this invention have been successfully tested with improvements fully demonstrated with regard to, e.g., lower weight, deflection, target accuracy, and heat dispersion characteristics. Further, barrel weight reductions of approximately 0.25 lbs. have been successfully accomplished, due to these helical openings. Temperatures as high as 909.5 degrees Fahrenheit peak temperatures were sustained for the barrel, even exceeding current operating amounts.

(18) While the invention may have been described with reference to certain embodiments, numerous changes, alterations and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.