Title:
Ammunition
Kind Code:
A1


Abstract:
Ammunition utilizing sabots that extend more forward than the bullets they at least partially encase. The sabots may be formed from one or more pieces. The one-piece sabots may include one or more arms.



Inventors:
Byer, Troy Lee (Great Bend, KS, US)
Application Number:
11/007823
Publication Date:
02/09/2006
Filing Date:
12/08/2004
Primary Class:
International Classes:
F42B14/06
View Patent Images:
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Primary Examiner:
HAYES, BRET C
Attorney, Agent or Firm:
NORTON ROSE FULBRIGHT US LLP (AUSTIN, TX, US)
Claims:
1. A round of ammunition comprising: a case having a front end, a rear end and an opening in the front end; a sabot positioned in the opening, the sabot having a front end, a rear end and a cavity, the front end of the sabot positioned forward of the opening; and a bullet positioned in the cavity, the bullet having a front end and a rear end, the front end of the bullet positioned behind the front end of the sabot.

2. (canceled)

3. (canceled)

4. The round of claim 1, the bullet having a rear portion with a contour, and the cavity of the sabot being defined by a rear portion having a contour that matches the contour of the rear portion of the bullet.

5. The round of claim 1, the cavity of the sabot having a side wall and a rear wall, the side wall meeting the rear wall at a right angle.

6. The round of claim 1, the sabot including at least one arm, the arm having an end.

7. The round of claim 6, the sabot including at least two arms, each arm having an end.

8. The round of claim 7, the ends of the arms positioned in a closed formation so as to cover the front end of the bullet.

9. The round of claim 7, the ends of the arms positioned in an open formation so as not to cover the front end of the bullet.

10. The round of claim 9, the cavity of the sabot having a forward portion that includes an ogive shoulder preventing the front end of the bullet from being positioned even with or forward of the front end of the sabot.

11. The round of claim 7, the arms being spaced apart from each other by separators, each separator extending from the front end of the sabot toward the rear end of the sabot and terminating prior to the rear end of the sabot at a separator termination point.

12. The round of claim 11, the sabot including a rear wall and a notch extending from each separator termination point to the rear wall.

13. The round of claim 11, the cavity of the sabot having a forward portion that includes an ogive shoulder preventing the front end of the bullet from being positioned even with or forward of the front end of the sabot.

14. The round of claim 1, the sabot including at least three arms, each arm having an end.

15. (canceled)

16. The round of claim 1, the bullet being a .284-caliber bullet.

17. The round of claim 16, the sabot being a .308-caliber sabot.

18. (canceled)

19. (canceled)

20. The round of claim 1, the opening in the case being defined by a front end edge of the case, the sabot having a groove into which the front edge of the case is crimped.

21. The round of claim 1, the round configured to be fired from a .30-caliber rifle.

22. A round of ammunition configured to be fired from a rifle, the round comprising: a metallic case having a main body with a rear end, a neck with a front end, a tapered section connecting the front and rear ends and an opening in the front end; a polymer sabot positioned in the opening, the sabot a having a front end, a rear end and a cavity, the front end of the sabot positioned forward of the opening, the sabot also having at least two arms spaced apart by separators that extend from the front end of the sabot toward the rear end of the sabot; and a bullet positioned in the cavity, the bullet having a pointed front end and a rear end, the front end of the bullet positioned behind the front end of the sabot.

23. The round of claim 22, the round configured to be fired from a .30-caliber rifle.

24. The round of claim 22, the bullet being at least partially covered by a metallic jacket.

25. A round of ammunition comprising: a metallic case configured to be fired from a .30-caliber rifle, the case having a main body with a rear end, a neck with a front end, a tapered section connecting the front and rear ends and an opening in the front end; a polymer sabot positioned in the opening, the sabot a having a front end, a rear end and a cavity with an ogive shoulder, the front end of the sabot positioned forward of the opening, the sabot also having at least two arms; and a bullet positioned in the cavity, at least a portion of the bullet extending forward of the ogive shoulder, the bullet having a pointed front end and a rear end, the front end of the bullet positioned behind the front end of the sabot, the bullet being at least partially covered by a metallic jacket.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to ammunition. More specifically, the invention relates to ammunition utilizing sabots that extend more forward than the bullets they at least partially encase.

2. Description of Related Art

The years between the Civil War and the turn of the century were years of great innovation in the fields of firearms design and ballistic sciences. With the advent of self contained metallic cartridges, non-revolving cylinder repeating weapons became practical. Many new designs were tried and marketed, but only one has stood the test of time. From its genesis in the Henry Repeater to the present day Winchester® and Marlin® versions, the lever action carbine has earned and retained a place in the American Hunter's gun rack. The tubular magazine appears to be integral to the handling characteristics that have endeared lever actions to millions of hunters. Both Winchester® and SAVAGE have marketed lever actions without tubular magazine. Each was moderately successful, but neither has been able to curb the appeal of the “standard” lever action.

The cartridge that has become synonymous with the lever action carbine is the Winchester®.30-30. Developed at the end of the black powder era, it was adapted to smokeless powder during the industry's shift to smaller caliber higher velocity rounds. Married to the lever action rifle, the .30-30 cartridge's success is well known. Even though the .30-caliber lever action carbine was never a target or military rifle, its design and handling attributes as a hunting gun have allowed it to remained popular with outdoorsmen. And while bolt action and semi-automatic rifles have drawn many hunters, there are still thousands, if not millions, of hunters using .30-caliber lever action carbines in deer seasons year after year.

Thirty-caliber lever action carbines that utilize tubular magazines suffer from a drawback. In a conventional tubular magazine, the point of one round would rest on the primer of the next round. This situation invites disaster. As a result, .30-caliber lever action carbines with tubular magazines must utilize round nose or flat nose bullets. The shortcoming of this solution is the loss of energy associated with these bullets versus pointed bullets, such as spitzers.

It is generally accepted in the gun press that the minimum amount of terminal energy required to humanely take a deer is 1000 foot/ponds (ft/lbs). Hornady's Handbook of Cartridge Reloading, Third Edition, includes data related to the firing of a .308 caliber, 170 grain flat nose bullet at 2300 feet per second (fps). For such a bullet, the muzzle energy (i.e., the energy at the end of the muzzle) of the bullet is 1997 ft/lbs, the energy of the bullet at 100 yards from the end of the muzzle is 1319 ft/lbs (66% retained) and the energy of the bullet at 150 yards is down to 1064 ft/lbs (53% retained). According to the same publication, starting a .308-caliber 168 grain boat tail hollow point match (BTHPM) bullet (which is a bullet with a pointed front end) at the same 2300 fps, the muzzle energy is 1974 ft/lbs, and the energy at 100 yards is 1705 ft/lbs (86% retained). That is a 30%+increase of delivered energy at 100 yards. The BTHPM bullet still has 1078 ft/lbs (55% retained) at 400 yards. Stated more simply, having to use a flat nose bullet instead of a pointed bullet means less power at normal ranges, or a decrease in the useable range of the ammunition.

There have been at least two major attempts to put pointed bullets in tubular magazines. The French Label (1886) and a Remington® pump action both tried to use pointed bullets in a tubular magazine by canting the rounds so that the points and primers were offset. The French Label round had a circular trough on the head of the cartridge around the primer to catch the point of the next bullet. Neither design stood the test of time.

SUMMARY OF THE INVENTION

The present ammunition reduces or eliminates the shortcomings identified above. Each round of the present ammunition utilizes a sabot as part of a solution to those shortcomings. As used in this document, a “sabot” is a structure that at least partially encases a bullet as the two travel down the muzzle of a weapon. The sabot should be discarded, or fall away from the bullet, after the bullet exits the muzzle. The present ammunition uses sabots that extend more forward than the bullets they at least partially encase. As a result, a round of the present ammunition that is placed in a tubular magazine is not likely to set off the primer of the round in front of it because the front end of the sabot, rather than the less forward front end of the point of the bullet, is in contact with the head of the more forward round. Consequently, using the present ammunition, it is possible to take advantage of the use of pointed bullets in tubular magazines without modifying any aspect of the firearm.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings demonstrate certain aspects of some of the present rounds of ammunition. The drawings illustrate by way of example and not limitation. Like reference numbers refer to similar elements. The drawings are not to scale.

FIG. 1 is a perspective view of one of the present rounds of ammunition.

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1.

FIG. 3 is an elevational view of a portion of the round of ammunition shown in FIG. 1.

FIG. 4 is a partial sectional view of the bottom portion of one of the present sabots.

FIG. 5 is a top view showing an open configuration of the arms of one of the present sabots.

FIG. 6 is a top view showing a closed configuration of the arms of one of the present sabots.

FIG. 7 is an elevational view of one of the present sabots in which the separators are slots.

FIG. 8 is a top view showing the arms of the sabot in FIG. 7 in an open configuration.

FIG. 9 is a top view showing the arms of the sabot in FIG. 7 in a closed configuration.

FIG. 10 is an elevational view of one of the present sabots that has only one arm.

FIG. 11 is a top view of the sabot in FIG. 10.

FIG. 12 is a top view of one of the present sabots that has two arms in an open configuration.

FIG. 13 is a top view of one of the present sabots that has two arms in a closed configuration.

FIG. 14 is a top view of one of the present sabots that has four arms in an open configuration.

FIG. 15 is a top view of one of the present sabots that has five arms in an open configuration.

FIG. 16 is a top view of one of the present sabots that has six arms in an open configuration.

FIG. 17 is a side view of a portion of an arm of one of the present sabots.

FIG. 18 is a view of the inside of the portion shown in FIG. 15.

FIG. 19 is a side view of a portion of another arm of one of the present sabots.

FIG. 20 is a view of the present rounds of ammunition loaded in the tubular magazine of a lever action rifle; the figure also shows one of the present sabots and the bullet the sabot at least partially encases traveling down the bore of the barrel after being fired, and the arms of one of the present sabots flaring after the two items exit the barrel.

FIGS. 21-28 are charts depicting ballistic data relating to the performance of various .308-caliber flat nose and round nose bullets versus the performance of various 284-caliber pointed bullets.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In this document (including the claims), the terms “comprise” (and any form thereof, such as “comprises” and “comprising”), “have” (and any form thereof, such as “has” and “having”), and “include” (and any form thereof, such as “includes” and “including”) are open-ended linking verbs. Thus, a round of ammunition or an aspect of a round that “comprises,” “has,” or “includes” one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements.

For example, a sabot having a front end, a rear end and a cavity has at least a front end, a rear end and a cavity, but is not limited to only having a front end, a rear end and a cavity. For example, such a sabot may also have two or more arms.

The terms “a” and “an” mean one or more than one. The term “another” means at least a second or more. The term “multiple” means two or more. The term “substantially” means at least approaching a given state (e.g., preferably within 10% of, more preferably within 1% of, and most preferably within 0.5% of, each of these ranges including the given state).

Those of skill in the art will appreciate that in the detailed description below, certain well known components and assembly techniques are omitted so as not to obscure the present rounds of ammunition in unnecessary detail.

The present ammunition uses sabots to prevent point-to-primer contact between consecutive rounds in a tubular magazine, and to prevent damage to the points of bullets that are at least partially encased in the sabots. The present sabots, like traditional sabots, allow a smaller-caliber bullet to be fired from a larger-caliber firearm. Like traditional sabots, the present sabots serve to substantially seal the space between the bore and the bullet. As a result, most if not all of the expanding gases from the ignited powder will not escape around the smaller caliber bullet as the two travel down the barrel. Instead, substantially all of the gases will propel the sabot and bullet down the barrel as if the bullet were large enough to fill the bore.

Sabots are not new. Conventional sabots are usually made of plastic or a light weight synthetic material and are discarded shortly after the round leaves the barrel. Sabot technology has been used with black powder and shotgun slugs. Current shotgun slug technology uses a full length sabot positioned around and extending more forward than an hour glass-shaped slug for use in rifled slug barrels. An example of sabot use with shotgun technology is U.S. Pat. No. 6,105,506.

Sabots have been used in high powered rifles as well. Remington® ACCELERATOR ammunition used sabots to load .22 caliber varmint bullets into larger caliber rounds like .30-06 and .30-30. The purpose of this was to make a hunter's large game rifle more versatile. However, the ACCELERATOR ammuntion solved a non-existent problem and/or did not take into account the number of varmint hunters that reloaded or the accuracy requirements of varminting. Remington® ACCELERATOR ammunition was discontinued in 1998, although some such ammo is still available in the market. While the ACCELERATOR line was not a success, it does prove the safety and feasibility of using a sub-caliber bullet with a sabot in high powered rifles.

Sabots have been used with other ammunition as well. For example, 120 mm Main Battle Tank ammunition is called “Fin Stabilized Discarding Sabot.”

Turning to the present ammunition, FIG. 1 shows one example of the present rounds. Round 100 includes case 10, which has front end 12, rear end 14 and opening 16 in front end 12. Case 10 includes main body 13, neck 17, and tapered section 15 connecting main body 13 and neck 17. Case 10 also includes head 11, rim 18 and primer 19 centered in head 11. Sabot 20, one of the present sabots, is positioned in opening 16. Sabot 20 has front end 22 positioned forward of opening 16. Sabot 20 also has cavity 26, in which bullet 30 is positioned.

The front end (not visible) of bullet 30 is positioned behind front end 22 of sabot 20. As a result, when round 100 is loaded into a tubular magazine behind another round, front end 22 of sabot 20 will contact the head of the more forward round, instead of the point of bullet 30 contacting the primer of the more forward round. This will help to prevent damage to the point of the bullet. This will also help to prevent the point of the bullet from setting off the primer of the more forward round.

Sabot 20 also includes three arms 46. The arms are spaced apart from each other and separated by separators that are shown in other figures in more detail. The separators are cuts in the wall of the sabot that extend from the outer surface of the sabot to the inner surface of the sabot. The separators make it easier for the arms of the sabot to bend outwardly, or flare, from the center of the sabot when a bullet is inserted into the cavity of a one-piece sabot. The separators also make it easier for the arms of the sabot to flare as the sabot and bullet exit the barrel of the firearm, facilitating separation of the sabot from the bullet.

FIG. 2 is a cross-sectional view of round 100 taken along line 2-2 from FIG. 1. FIG. 2 shows the interior of case 10, and reveals that main body 13 houses propellant 40 next to primer 19. Propellant 40 may be a powder of the type conventionally used in rifle, pistol, or shotgun ammunition. The amount of propellant 40 used in a given case will be based largely on the desired load. In operation, the firing pin of the firearm from which round 100 is shot will strike primer 19, which will, in turn, ignite propellant 40, driving sabot 20 and bullet 30 forward.

As shown in FIG. 2, sabot 20 includes rear end 24 and cavity 26. Sabot 20 also includes a groove in outer surface 43, into which front edge 21 of case 10 is crimped. This crimp will help to hold bullet 30 in place during recoil and as the round is transferred from the magazine to the chamber. Bullet 30 includes front end 32 and rear end 34. As FIG. 2 shows, front end 22 of sabot 20 is positioned more forward than front end 32 of bullet 30. Stated another way, front end 32 of bullet 30 is positioned behind front end 22 of sabot 20.

Continuing with FIG. 2, cavity 26 includes a side wall 42 and a rear wall 44. Bullet 30 includes boat tail 39. In the example of cavity 26 shown in FIG. 2, the contour of cavity 26 does not match the contour of boat tail 39 because side wall 42 meets rear wall 44 at a right angle. In another alternative, side wall 42 may meet rear wall 44 in a way that gives cavity 26 a contour that matches the boat tail or other contour of the rear portion of bullet 30.

Sabot 20 also includes three arms 46, only two of which are shown in FIG. 2. Arms 46 have ends 52, which are defined by arm end surfaces 54. As shown in FIG. 2, arm end surfaces 54 may be flat. As a result, any pressure by round 100 on the head of a round that is in front of round 100 in a tubular magazine will be spread out over arm end surfaces 54. Alternatively, ends 52 of arms 46 may be rounded instead of being defined by a flat surface as shown in FIG. 2. In other embodiments, arm end surfaces 54 may be slanted slightly either inwardly (i.e., into front end 32 of bullet 30) or outwardly. Whatever the shape of ends 52 of arms 46, the arms should not be configured to contact primer 19 with a point or sharp end.

Continuing with FIG. 2, each arm 46 also includes an ogive shoulder 47. The ogive of a bullet is the curved portion of the bullet's forward end. The ogive of a bullet begins where the bearing surface of the bullet ends. The bearing surface of the bullet is the cylindrical section near the middle of the bullet. Typically, the bearing surface of a bullet is the portion of a bullet that touches the bore of a barrel as the bullet travels down the barrel. On each arm, ogive shoulder 47 terminates at ogive shoulder end 56. Because the present ogive shoulders (as shown in FIG. 2) substantially follow the contour of the ogive of the bullets used with the present rounds, the bullets should not move forward past the present ogive shoulder ends either in the magazine or chamber, or traveling down the barrel. In order to protect against the bullets in the present sabots moving forward, the properties of the material chosen for the sabot (such as stiffness) should be taken into account. In addition, the amount of surface area of the present ogive shoulders that contacts the outer surface of the bullet will also factor into the final configuration of the sabot. If the sabot is made from one piece of material and is designed with a slight amount of ‘give’ in the arms, the extent to which the bullet will move forward as a result of that give during recoil or cycling through the action may not exceed the distance between the front end of the bullet and the front end of the sabot.

FIG. 3 shows sabot 20 intact within a partial sectional view of case 10. FIG. 3 shows that arms 46 of sabot 20 are spaced apart from each other by separators, only 2 of which are visible. The embodiment of the separators in FIG. 3 take the form of curved spaces 47 near the front end 22 of sabot 20. The separators then take the form of slots 49, which extend from the rear end of curved spaces 47 toward rear end 24 of sabot 20. The separators terminate at separator ends 48, which are in front of rear end 24 of sabot 20. The location of the termination point may be chosen so that gas from the ignited powder is unlikely to escape through the separators and around the bullet, the sabot, or both. The separators shown in FIG. 3 extend from the front end of sabot 20 toward the rear end of sabot 20. As explained above, for a one-piece sabot, the separators make it possible to bend back the arms of the sabot in order to insert the bullet into the cavity of the sabot during the manufacturing process. They also promote flaring of the arms of the arms of the sabot, and thus expeditious separation of the sabot from the bullet, as the sabot and bullet exit the barrel of the firearm.

FIG. 4 is a partial cross-sectional view of the bottom portion of sabot 20. FIG. 4 shows portions of each of arms 46 and slots 49 of the three separators. In order to further facilitate the separation of sabot 20 from bullet 30 (not shown) after the two exit the barrel, a groove 51 may be carved into inner surface 26 of sabot 20 and extend from separator end 48 of each separator to rear surface 44. Although not shown, such grooves may extend toward rear surface 44 and terminate short of rear surface 44. These grooves need not have any special shape. They may be rounded as shown in FIG. 4, or they may have a V-shape, a square-shape, or any other suitable shape that will promote failure along the groove. These grooves may be provided on the inner surface of the cavity of the sabot instead of the outer surface of the sabot in order to avoid gases escaping around the outside of the sabot during firing. Further, the grooves are intended to facilitate the flaring of the arms after the sabot and bullet exit the barrel, such that the arms of the sabot are peeled back rapidly away from the bullet.

The separators are intended to facilitate peeling back to the separator ends 48. In embodiments of the present sabots that further include grooves extending from separator ends toward rear surface 44, the arms will continue to separate from each other along the failure points created by the grooves. As a result of this separation, the sabot may more easily separate from the bullet after the two exit the barrel.

FIGS. 5 and 6 show top views of different versions of the present rounds of ammunition. Specifically, these figures illustrate two different versions of the present sabot. FIG. 5 is a top view of round 100. In FIG. 5, bullet 30 has been provided with a distinct tip 33. Tip 33 may be formed from a different material than some or all of bullet 30 so as, for example, to promote the mushrooming of the bullet. Alternatively, tip 33 may be a portion of bullet 30 that is coated with a metal or other substance used as an identification source by an ammunition manufacturer. Examples of such tipped bullets include Winchester's® Silvertip® bullets and Nosler's® BALLISTIC TIP bullets. Tip 33 may comprise a color-coded insert made of a polymer.

In FIG. 5, the ends (element numbers have been omitted so as not to clutter the figure) of arms 46 are arranged in an open configuration such that front end 32 of bullet 30 is not covered and is visible from the top. In addition, a portion of tip 33 is visible as well. The open configuration shown in FIG. 5 has a number of benefits. It increases the likelihood that sabot 20 will catch enough air as sabot 20 and bullet 30 exit the barrel for the arms of sabot 20 to peel back and for sabot 20 to fall away from bullet 30. The open configuration also allows tip 33 to be viewed from the top, enhancing any source-identifying function tip 33 may serve.

The difference between the sabot in FIG. 5 and the sabot in FIG. 6 is in the configuration of the ends of the arms. In FIG. 6, the ends (element numbers have been omitted so as not to clutter the figure) of arms 46 are arranged in a closed configuration such that they cover the front end of bullet 30. While this closed configuration is not necessary to prevent contact between the front end of bullet 30 and the head a more forward round in a chamber, the closed configuration does add an extra layer of protection in this regard.

As shown in both FIGS. 5 and 6, the top portion of the separators, which are near the front end of sabot 20, may have a teardrop or teardrop-like shape. Many other shapes may be used, however, including circle or circle-like shapes, oval or oval-like shapes, and the like. Furthermore, many different styles of arms are possible.

For example, FIG. 7 shows a version of sabot 20 in which arms 46 are spaced apart from each other by separators that take the form of slots 49 extending from front end 22 of sabot 20 to separator ends 48. FIGS. 8 and 9 shows top views of the sabot depicted in FIG. 7, and illustrate that the sabot from FIG. 7 may be provided with grooves 51. FIG. 8 shows an open configuration of the ends of arms 46, and FIG. 9 shows a closed configuration of the ends of arms 46.

FIGS. 10 and 11 show an elevational and side view, respectively, of one of the present sabots that has only one arm 46. As shown in FIG. 11, this version of sabot 20 does include slots 49 and grooves 51.

FIGS. 12-16 show additional examples of the present rounds of ammunition, the sabots of which have different arm and separator configurations than those shown in previous figures. FIG. 12 is a top view of round 100 in which sabot 20 includes only two arms 46. The separators separating the two arms begin as large curved spaces and then narrow to slots 49. Also included in sabot 20 in FIG. 12 are grooves 51. Arms 46 in FIG. 12 are oriented in an open configuration such that front end 32 of bullet 30 is not covered by sabot 20. The ends of the arms in FIG. 12 are not characterized by arm end surfaces 54. Instead, outer surface 43 of sabot 20 has no sharp change of angle near the ends of the arms. FIG. 13 shows a two-armed sabot 20. Arms 46 are in a closed configuration in FIG. 13. Further, like the sabot in FIG. 12, arm end surfaces do not characterize the ends of arms 46 in FIG. 13. Sabot 20 in FIG. 13 does not include grooves 51. FIG. 13 illustrates the ends of arms 46 may take on a variety of shapes, including one that bulges slightly near the ends of the arms.

FIGS. 14-16 show different versions of round 100 in which the number of arms increases from four to five to six, respectively, and the shapes of the top portions of the separators decreases with the increase in the number of arms. The ends of the arms of each sabot in these figures is in an open configuration, although a closed configuration may also be used in each instance. In addition, the arms of the sabots in each of FIGS. 14-16 have curved surfaces near their ends.

The design of the present sabots will depend on multiple factors, including the diameter of the bore of the firearm from which the round will be fired, the diameter and weight of the bullet, and the material chosen for the sabot. The present sabots may be formed from a variety of materials. Most modern sabots for use in sporting guns are injection molded from heat resistant polycarbonate plastic or nylon. These compounds will resist temperatures up to 500 degrees Farenheit and are formed in one piece, with a recess for the base of the bullet and four to six fluted fingers at the front of the sabots.

The present sabots may be made from these same materials. Another potentially suitable material for the present sabots is pot metal, which may include a mixture of tin, antimony and lead; alternatively, a low-grade brass or copper-lead alloy containing both zinc and tin may be used. Powdered metals may also be used to form the present sabots.

One purpose of the present sabots is to extend more forward than the bullets they at least partially encase. This helps to prevent damage to the front end of the bullet and, as a result, helps the bullet to stay on its intended path after firing. It also helps to prevent contact between the front end of the bullet and the primer of the more-forward round in the magazine. The present sabots should be configured such that they achieve this purpose. In addition, the present sabots should be configured such that the escape of gases around the sub-caliber bullet the sabot at least partially encases is minimized. The forward portion of the sabot should be configured such that it cycles substantially smoothly through the action of the firearm, but contain enough air catching surface that the sabot separates from the bullet shortly after exiting the muzzle. By providing the present sabot with arms, which may be separated from each other by the separators described above, the air drag on the sabot as it exits the muzzle should tend to bend the arms outwardly. As a result, the surface area of the sabot exposed to the air drag should increase and further slow the sabot, allowing the bullet to continue on its intended path, and leaving the sabot behind the bullet and falling away from the bullet.

An example of one arm of a sabot with a configuration that may achieve the smooth cycling and air drag functions is shown in FIG. 17. This side view of a portion of arm 46 shows that the shape of outer surface 43 of the sabot and, thus, arm 46, may have substantially the same contour as the outer surface of a flat nose bullet having the same caliber. In other words, if the arm shown in FIG. 17 is part of a sabot designed as a .30-caliber sabot for use with a 7 mm bullet (the designation “7 mm” in this document is shorthand for .284 caliber), outer surface 43 may be given substantially the same contour as the outer surface of a flat nose .30-caliber (the designation “.30 caliber” in this document is shorthand for .308 caliber) bullet. Similarly, arm end surface 54 may meet outer surface 43 at a substantially sharp angle, just as the end surface of a flat nose bullet meets the outer surface of a flat nose bullet. Dimension w1 shown in FIG. 17 may be adjusted as necessary to maximize the muzzle velocity of the bullet that the sabot at least partially encases. Dimension w1 may also be adjusted to maximize the speed with which the sabot falls away from the bullet after exiting the muzzle.

Continuing with FIG. 17, as shown, ogive shoulder 47 may terminate at its forward end at ogive shoulder end 56. Inner forward surface 60, which is a portion of inner surface 26 (as is ogive shoulder 47), is positioned forward of ogive shoulder end 56. The position of ogive shoulder end 56 relative to end 52 of arm 46 may be adjusted to maximize the stability of the bullet that is at least partially encased by the sabot. It is contemplated that minimizing the surface area of inner forward surface 60 by moving ogive shoulder end 56 closer to end 52 of arm 46 will further stabilize the bullet. It is also contemplated that maximizing the surface area of inner forward surface 60 will increase the speed with which the sabot falls away from the bullet after exiting the muzzle. Inner side 62 of arm 46 is shows as meeting arm end surface 54 at a right angle. However, inner side 62 may meet arm end surface 54 at an acute angle or an obtuse angle. Furthermore, the substantially sharp angles at which arm end surface 54 meets inner side 62 and at which inner side 62 meets inner forward surface 60 may, alternatively, be rounded. The arm shown in FIG. 17 may be used alone as shown in FIG. 10 or with any other suitable number of arms. As a result, one of the present sabots using arm 46 as shown in FIG. 17 may include a total of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more such arms.

FIG. 18 is a view of the inner surface of the portion of arm 46 shown in FIG. 17.

FIG. 19 is a side view of another example of an arm of one of the present sabots. In this figure, outer surface 43 and arm end surface 54 shown in FIG. 17 have been merged smoothly into outer surface 43′, which more closely approximates the outer surface contour of a round nose bullet of the same caliber. In other words, if the arm shown in FIG. 19 is part of a sabot designed as a .30-caliber sabot for use with a 7 mm bullet, outer surface 43′ may be given substantially same contour as the outer side surface of a round-nose .30-caliber bullet. Also in FIG. 19, inner forward surface 60 and inner side 62 shown in FIG. 17 have been merged smoothly into inner forward surface 60′.

FIG. 20 shows how using the present rounds allow for the use of pointed bullets in tubular magazines. FIG. 20 shows a lever action rifle 90 that includes a barrel 92 and a tubular magazine 94; barrel 92 includes bore 93. The length of the tubular magazine has been shortened for simplicity, and not all the working elements of rifle 90 are shown for the same reason. Additionally, the view in FIG. 20 is a sectional one, but the cross hatching that would otherwise characterize the sectioned elements of rifle 90 have been omitted for simplicity. Two rounds 100 are shown positioned in magazine 94. Because the round 100 closest to the action of rifle 90 includes sabot 20 having a front end that is more forward than the front end of the bullet it at least partially encases, the front end of that bullet is protected from striking the primer of the more forward round during cycling of the rounds through the action and during recoil. FIG. 20 also shows bullet 30 and sabot 20 traveling down bore 93 of barrel 92 after the bullet has been fired. As the bullet and sabot exit barrel 92, FIG. 20 shows the arms of sabot 20 flaring and slowing as bullet 30 continues on its intended path.

Examples of sabots that were commercially available at the time this application was filed include those from J & D Components in Orem, Utah, which provides .30-caliber sabots for .22-caliber bullets (the designation “.22-caliber” in this document is shorthand for .224-caliber) and .50-caliber sabots (the designation “.50-caliber” in this document is shorthand for .508-caliber) for .30-caliber bullets. Remington's® ACCELERATOR ammunition was loaded with .30 caliber sabots containing .22-caliber, 55 grain bullets for the .30-06, the .308 Winchester® and the .30-30 Winchester® cartridges. Remington® reported muzzle velocities of 4,080 fps for the .30-06, 3,770 fps for the .308 and 3,400 fps for the .30-30 ammunition. The sabots for these cartridges were not placed more forward then the front end of the bullets they were at least partially encasing, nor was there any need for them to be.

Using the present rounds of ammunition, it is possible to store pointed bullets in tubular magazines. Furthermore, using the present rounds of ammunition, it will now be possible to capitalize on the ballistic advantages pointed bullets have over round nose and flat nose bullets without any modification to the firearm itself. FIGS. 21-28 illustrate these advantages. The Hornady data in FIGS. 19-26 came from the Hornady Handbook of Cartridge Reloading, Third Edition, ©1980. The Nosler® data in FIGS. 21-28 came from Nosler Reloading Manual, Number Three, ©1989. The .284-caliber bullets in these figures were not fired with the present sabots.

FIG. 21 is a graph showing the terminal energy of a .308-caliber, 170 grain flat point bullet (the .308-caliber Hornady 170 grain Flat Point) versus the terminal energy of various .284-caliber pointed bullets ranging in weight from 160 grain to 175 grain.

FIG. 22 is a graph showing the terminal energy of a .308-caliber 150 grain round nose bullet (the .308-caliber Hornady 150 grain Round Nose 2400) versus the terminal energy of various .284-caliber pointed bullets ranging in weight from 140 grain to 150 grain.

As FIGS. 21 and 22 illustrate, considering that the terminal energy required to humanely take a deer is 1000 ft/lbs, the humane firing range of a pointed .284-caliber bullet is roughly 400 yards versus about 150 yards for a round nose or flat nose .308-caliber bullet of comparable weight.

FIGS. 23 and 24 illustrate in bar graph form the differences in terminal energy shown linearly in FIGS. 21 and 22.

FIGS. 25 and 26 illustrate the velocity retention of the .308-caliber, 170 grain flat point bullet from FIGS. 21 and 23 versus the velocity retention of the various .284-caliber pointed bullets ranging in weight from 160 grain to 175 grain from FIGS. 22 and 24.

FIGS. 27 and 28 illustrate the trajectory of the .308-caliber, 170 grain flat point bullet from FIGS. 21, 23 and 25 versus the trajectory retention of the various .284-caliber pointed bullets ranging in weight from 160 grain to 175 grain from FIGS. 22, 24, and 26.

As provided in TABLE 1, the present rounds of ammunition may be used with the following caliber sabots at least partially encasing the following caliber pointed bullets:

TABLE 1
Sabot CaliberBullet Caliber
7 mm (.284)6 mm (.243 inches)
.257 inches (typically referred
to as .25-caliber)
6.5 mm (.264 inches)
.277 inches (typically referred
to as .270-caliber)
.308 inches (typically referred6 mm (.243 inches)
to as .30-caliber).257 inches (typically referred
to as .25-caliber)
6.5 mm (.264 inches)
.277 inches (typically referred
to as .270-caliber)
7 mm (.284 inches)
.375 inches (typically referred6 mm (.243 inches)
to as .38-caliber).257 inches (typically referred
to as .25-caliber)
6.5 mm (.264 inches)
.277 inches (typically referred
to as .270-caliber)
7 mm (.284 inches)
.308 inches (typically referred
to as .30-caliber)
.312 inches (typically referred
to as 303 or 7.7 mm)
8 mm (.323 inches)
.338 inches
.358 inches (typically referred
to as .35-caliber)
.430 inches (typically referred6 mm (.243 inches)
to as .44-caliber).257 inches (typically referred
to as .25-caliber)
6.5 mm (.264 inches)
.277 inches (typically referred
to as .270-caliber)
7 mm (.284 inches)
.308 inches (typically referred
to as .30-caliber)
.312 inches (typically referred
to as 303 or 7.7 mm)
8 mm (.323 inches)
.338 inches
.358 inches (typically referred
to as .35-caliber)
.375 inches (typically referred
to as .38-caliber)
.458 inches (typically referred6 mm (.243 inches)
to as .45-caliber).257 inches (typically referred
to as .25-caliber)
6.5 mm (.264 inches)
.277 inches (typically referred
to as .270-caliber)
7 mm (.284 inches)
.308 inches (typically referred
to as .30-caliber)
.312 inches (typically referred
to as 303 or 7.7 mm)
8 mm (.323 inches)
.338 inches
.358 inches (typically referred
to as .35-caliber)
.375 inches (typically referred
to as .38-caliber)
.416 inches

The .30-caliber sabots listed above in TABLE 1 may be positioned in the openings of .30-caliber cartridges and fired from any suitable firearm, including a .30-30 lever action carbine rifle with a tubular magazine, such as the Winchester® .30-30 lever action rifle. However, such the rounds of ammunition that include such sabots may be fired from other firearms of the appropriate caliber, including those without tubular magazines, such as handguns.

The .45-caliber sabots listed above in TABLE 1 may be positioned in the openings of .45-caliber cartridges and fired from any suitable firearm, including a .45-70 lever action carbine rifle with a tubular magazine, such as those made by Winchester®, Marlin®, and some importers. However, such the rounds of ammunition that include such sabots may be fired from other firearms of the appropriate caliber, including those without tubular magazines, such as handguns.

The components of the present rounds of ammunition described above need not be made in the exact disclosed forms, or combined in the exact disclosed configurations. Instead, it will be clear that various substitutions, modifications, additions and/or rearrangements of the features of the present rounds of ammunition may be made without deviating from their scope, which is defined by the claims and their equivalents. For example, .45-caliber cases for the .45-caliber sabots listed in TABLE 1 have straight wall cases, rather than cases with a tapered portion connecting a main body and a neck as do the .30-caliber cases shown in the present figures. That is, .45-caliber cases have a main body with a length that extends substantially from the rear end of the case to the front end of the case, the main body having a diameter that is substantially constant along the length. Additionally, .30-caliber cases with straight walls may also be used.

As another example, the cases used with the present rounds of ammunition may lack a rim. As another example, instead of groove that extends around the outer surface of the sabot and into which the front edge of the case may be crimped, the present sabots may be secured to the cases with a friction fit, provided the friction fit is tight enough to withstand the forces associated with recoil and with cycling rounds through the action of the firearm, whichever forces are greater. Alternatively, the present sabots may be provided with crimping notches that are spaced apart from each other. In such an embodiment, 2, 3, 4, 5, 6, 7, or more notches may be provided in the outer surface of the sabot and the adjacent portions of the front edge of the case may be crimped into those notches.

As another example, although the present sabots have been illustrated as having a cylindrically-shaped rear end as opposed to a boat tail-shaped rear end, a boat tail configuration may be provided on the rear end of the present sabots, provided the same does not interfere with the gas sealing function of the present sabots.

As yet another example, the sabots illustrated in the figures are made from one piece of material and include separators that extend beyond the bearing surfaces of the bullets toward the rear end of the sabots. However, the present sabots may be formed from multiple pieces and separators in addition to the cuts used to create the separate pieces need not be provided. For example, one of the present sabots may have an external configuration as shown in FIG. 7, but lack slots 49. Instead, a cut in the sabot that is more narrow than slots 49 may be provided in the sabot to divide it into two halves. During the manufacturing process, the two halves may be placed around a bullet and sealed at the rear portion of the sabot with a substance that will burn off when exposed to the ignited powder. Other suitable sealers include adhesives such as spirit glue and LOCTITE adhesive, along with substances like finger nail polish. Alternatives to such sealers include paper patch, tape, and cellophane wrap. The sealer may be applied prior to positioning the sabot in a case. As the bullet and sabot exit the barrel, the two halves will fall away from the bullet. Instead of two pieces, the same manufacturing process may be used to create a sabot with 3, 4, 5, 6, or more pieces.

Another alternative that is not shown in the figures is to use a bullet with the present rounds of ammunition that is covered partially or completely by a jacket, such as a metallic jacket.

The claims are not to be interpreted as including means-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for.”