This application is the U.S. National Stage of International Application Number PCT/FI2011/050032 filed on Jan. 17, 2011 which was published in English on Jul. 26, 2012 under International Publication Number WO 2012/98283, which application is hereby incorporated by reference.
The invention relates to a firearm which is arranged modifiable by the user such that the barrel of the firearm is arranged replaceable by the user. The invention particularly relates to a so-called firearm with a replaceable barrel which is arranged modifiable by the user such that a firearm calibre or some other property within the same calibre, such as twist rate or type, is arranged changeable by the user by replacing the barrel. The invention also relates to a firearm the barrel of which is a rifle barrel and which is arranged for a high-pressure centrefire cartridge.
The invention further relates to a firearm system which includes at least two barrels of different calibres replaceable by the user with their applicable attachments. At the moment of writing this application, such commercially interesting combinations are e.g. a firearm system arranged for three different calibres, the calibres of which are 308 Win, 300 Win Mag and 338 Lapua Magnum. Then, the same firearm is applicable as for its calibre to cost-effective practice shooting and versatile precision or target shooting and, with larger cartridges, particularly to long-distance precision shooting in the use of either civilians or authorities. Naturally, it is possible to fit in this firearm system by following the same concept almost whichever calibres, such as 222 Rem, 223 Rem, 7.62*39, 30-06, 300 WSM up to the order of .50 BMG and more. The invention is also applicable to firearms employing other types of cartridges, such as low-pressure centre- and rimfire cartridges. Then, one calibre of the firearm system can be e.g. such a calibre employing some other type of cartridge.
Of prior art is known, inter alia, U.S. Pat. No. 7,451,564 which describes an interchangeable barrel system for rifles.
Of prior art is also known U.S. Pat. No. 7,076,904 which describes an arrangement related to a detachable gun barrel.
In the context of this specification, the term ‘forward’ or ‘front direction’ refers to the firearm barrel direction i.e. the direction in which a projectile flies when a cartridge in the firearm is fired. Correspondingly, the term ‘backward’ or ‘rear direction’ refers to the firearm butt direction which is thus the opposite direction of ‘front direction’. A barrel line refers to a line which is at the centre of the barrel, whereby e.g. the centre of rotation of the bullet being shot travels along the barrel line the bullet still being in the barrel. In the context of this specification, a piece sent by the firearm is referred to with the general term of projectile which can be e.g. a bullet, a shell or equivalent.
Equivalently for clarity, in the context of this application, a calibre refers to a cartridge intended for the firearm and firearm properties possibly defined by it, whereby calibres are e.g. 222 Rem, 223 Rem, 7.62*39, 308 Win, 30-06, 300 WSM, 300 Win Mag, 338 Lapua Magnum and so on. In this context, different calibres can also refer to a change arranged within a calibre of the same name or a differing property, such as a change in rifle twist rate or type. An example of such classified here as different calibres is 308 Win having the rifle twist rate of 8 inches per round and 308 Win having the rifle twist rate of 12 inches per round.
An object of the invention is to provide a precision rifle having a replaceable barrel, the barrel of which is freely-floating i.e. the firearm barrel only contacts the other firearm constructions about in the area of the cartridge chamber. An object of the invention is to provide a firearm the calibre of which is changeable by replacing the barrel and which firearm is capable of particularly high precision. An object of the invention is to provide a firearm system which is arranged modifiable by the user such that the barrel of the firearm is arranged replaceable by the user. A further object is that, with the different calibres of the firearm system, the operating properties of the firearm are equivalent to a firearm arranged only for one calibre.
The firearm according to the invention is characterised by the firearm comprising
The firearm system according to the invention is again characterised by the firearm system comprising a firearm according to claim 1, in which a firearm calibre is arranged replaceable by the user by replacing a barrel unit, a bolt or a bolt locking piece and optionally a cartridge magazine. The bolt can have been composed so-calledly of one piece, whereby the bolt is replaced, or it can have been composed of many pieces, whereby only the locking part is arranged replaceable by the user. Replacing the bolt is also optional as far as certain cartridges having a similar head, whereby the same bolt is suitable for several calibres.
A particular advantage of the construction according to the invention is that the barrel is provided freely-floating, whereby the firearm has the prerequisites for being precise. Particularly by means of the presented construction, the firearm is provided to operate repeatably in the same way of its zero, which has conventionally been a possible weak point of rifles with replaceable barrels. Traditionally, it is possible to make the rifles with replaceable barrels to operate accurately, but it has usually required test firing. Now with the firearm according to the present arrangement, the zero is provided at the same point with the important first shot even though the barrel had been replaced in the mean time for smaller calibre e.g. for test firings. The importance of the first shot is particularly high e.g. in the use of authorities whereby, in a situation involving firearms, the whole situation is aimed at resolving with one sole carefully calculated and precise shot. The same principle applies when using the firearm for hunting.
By rotating the clamping bush in the locked direction, the rear end of the locking piece is centerable and lockable by means of the rear cone to the cone in the receiver and the locking piece is of its front end centerable by means of the front cone and lockable by means of the centering bush cone and the radial expanding cylinder surfaces cocentrically to the cylinder surface in the receiver. Due to this property, the construction is relatively insensitive to the tightening torque of the clamping bush which in many known prior-art arrangements seems to change the firearm shot centre quite considerably.
An advantage of the arrangement according to the invention is that parts affecting the firearm accuracy and yet particularly precision and first shot accuracy, particularly the barrel, the locking piece and the bolt, can be positioned extremely repeatably cocentral, whereby the position and direction of the barrel line remain the same despite of detaching and attaching the barrel unit. Considerable heat created in the area of the cartridge chamber when firing cartridges repeatedly is also guided controllably away from the barrel unit via the front cone and the rear cone, whereby dimensional changes caused by thermal expansion does not affect the precision of the firearm by transferring the shot centre.
According to a feature, to the centering bush is rotatably connected a clamping bush having an outer thread which fits an inner thread in the receiver. This way, the construction is provided very compact and robust, whereby external factors cannot affect the critical point for firearm precision i.e. the joint formed by the barrel unit front cone, the centering bush and the inner cylinder surface of the receiver. Due to said inner thread, the clamping bush can be fitted to rotate partially within the receiver for protection. Hence, impacts applied to e.g. the forestock and accessories related to it, such as light amplifiers, lighting devices and equivalents when in use, do not affect the barrel fastening parts but the centering i.e. cocentricity always remains similar. The compact size provided by the property is also important for the accessories to fit well and to keep the total mass of the firearm appropriate, usually as light as possible. By means of the feature, the outside of the receiver front end can also be formed a practical fastening base for said accessories, the receiver front end can be manufactured e.g. as an external cylinder surface very accurate dimensionally, whereby the forestock can further be fastened on top of this external cylinder shape.
According to an embodiment, the receiver includes a locking piece guide which matches the equivalent shape in the locking piece, whereby the barrel unit is installable only in one position in relation to the receiver. Thus, the barrel unit sets by means of the guide always in the same position particularly in relation to the rotation axis around the barrel line. Then, the rear cone and the front cone also set at the same point and position in relation to the receiver.
A further advantage of the construction according to the invention is that the receiver can be manufactured of material for which machineability can be stressed compared to strength properties as selection criteria. By means of the presented construction, forces applied to the construction by pressure caused by shooting the firearm are centred mostly to the unit formed by the locking piece, the bolt and the barrel. The receiver is a relatively large piece having multidimensional shapes compared to the other parts of the firearm, due to which, manufacturing the receiver of high-strength steel would be arduous. Now, it is possible to manufacture the receiver of more easily machineable material, and no post-machining hardening is required or there is no need to provide so high strengths or hardnesses by means of possible tempering as in a construction in which pressure caused by firing affects the receiver directly.
According to an advantageous embodiment, the barrel and the locking piece are formed of different parts and connected together e.g. by means of a thread or a press fit. According to another embodiment, the barrel and the locking piece are formed one-piece i.e. of one piece, whereby the barrel unit is composed of one piece.
The invention will now be described in more detail with reference to the accompanying figures, in which figures:
a, 4b and 4c show a centering bush and a clamping bush according to an embodiment,
a and 6b show an arrangement for replacing a firearm barrel according to an embodiment,
a and 7b show a firearm system according to an embodiment, which employs two different cartridge lengths,
The locking piece 35 includes a guide 358 which matches a respective locking piece guide 208 in the receiver 20, whereby the barrel unit 3 is installable only in one position in relation to the receiver 20.
According to an advantageous embodiment, the barrel 30 and the locking piece 35 are formed of different parts and connected together e.g. by means of a thread or a press fit. According to another embodiment, the barrel 30 and the locking piece 35 are formed one-piece i.e. of one piece, whereby the barrel unit 3 is formed of one piece.
a and 4b show a centering bush and a clamping bush according to an embodiment. The centering bush 36 is arranged non-rotatable in relation to the locking piece 35 and both non-rotatable and expanding in the radial direction in relation to the receiver 20. The non-rotatability can be implemented e.g. by means of a groove 369 and a matching centering bush guide 209, whereby the centering bush cannot rotate in relation to the locking piece when the cone surface 366 of the centering bush slides along the equivalent front cone 356 of the locking piece. Simultaneously, a centering bush cylinder surface 367 expands in the radial direction and is locked in a receiver cylinder surface 207. To the centering bush 36 is rotatably connected the clamping bush 37 having an outer thread 372 which corresponds an inner thread 202 in the receiver.
b shows a cross section of a centering bush 36 and a clamping bush 37 according to an embodiment rotatably connected together. In
c shows an embodiment on how the centering bush 36 is installable fast in the clamping bush 37. By means of the groove 369, the centering bush is pressable somewhat smaller, whereby the grooves/notches seen in Fig. b are able to pass each other and the centering bush is locked in the clamping bush rotatably. In
a and 6b show an embodiment of the firearm system in which into connection with the bolt handle 22 is fitted a tool 224 which fits a tool stopper 374 on the circle of the clamping bush 37, whereby the clamping bush 37 is arranged openable by the user or tightenable using the bolt 21 as a tool.
a and 7b show a firearm, which belongs to a firearm system, which firearm system comprises at least two calibres, in which the maximum cartridge overall length between said two calibres differ moderately from each other, advantageously over 20 mm, whereby the action length of the bolt is arranged modifiable by the user by turning a bolt release lever 217. The length of the bolt motion is optimally as close as possible to such a length that an empty case exits the cartridge chamber and an unfired cartridge is fetched from the cartridge magazine and pushed to the cartridge chamber. Then, the bolt end has to go so far backwards that it passes the cartridge head in the cartridge magazine. When comparing e.g. cartridges in the calibres of 308 Win and 338 Lapua Magnum, it is possible to see that, checked from the table, the largest standard cartridge overall length of 308 Win is about 71.12 mm (2.8″) and the largest standard cartridge overall length of 338 Lapua Magnum is about 93.50 mm (3.681″). Then, the length of bolt action arranged for 308 Win can be referred to as short action and, correspondingly, the length of bolt action arranged for 338 Lapua Magnum can be referred to as long action. A long bolt path is not useful when using a short cartridge, most often on the contrary, as it can cause the user problems if the user's charge motion is not correct by routine.
In an embodiment of the firearm system according to the invention, this possible error situation is eliminated by means of the turnable bolt release lever, whereby the bolt action length is arranged modifiable by the user by turning the bolt release lever 217. It is seen in
As evident to those skilled in the art, the invention and its embodiments are not limited to the above-described embodiment examples. Expressions representing the existence of characteristics, such as “the firearm comprises a receiver”, are unlimited such that the description of characteristics does not exclude or prerequisite the existence of such other characteristics which are not presented in the independent or dependent claims.
Reference Numbers Used in the Figures
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/FI2011/050032 | 1/17/2011 | WO | 00 | 7/16/2013 |
Publishing Document | Publishing Date | Country | Kind |
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WO2012/098283 | 7/26/2012 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3538810 | Maillard | Nov 1970 | A |
5987797 | Dustin | Nov 1999 | A |
7076904 | Rustick | Jul 2006 | B1 |
7451564 | Wait | Nov 2008 | B2 |
8479429 | Barrett et al. | Jul 2013 | B2 |
20070240697 | Liao | Oct 2007 | A1 |
Number | Date | Country |
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434 220 | Aug 1935 | GB |
Number | Date | Country | |
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20130291420 A1 | Nov 2013 | US |