US20140082981A1

US20140082981A1 - Bolt action muzzle loading firearm

Info

Publication number: US20140082981A1
Application number: US13/591,374
Authority: US
Inventors: Kenneth E. Johnston
Original assignee: Individual
Current assignee: RA Brands LLC
Priority date: 2012-08-22
Filing date: 2012-08-22
Publication date: 2014-03-27
Also published as: US20140298702A1

Abstract

A muzzle loading firearm includes a barrel, a receiver, and a breech plug located at the breech end of the barrel. An insert integral with or attached to the breech plug provides sealing engagement against an opening in a cartridge case. The breech plug and insert together define a bore to allow a flame from an ignited primer on a cartridge casing to travel to a projectile propellant at the breech end of the barrel. A bolt without conventional lugs is movable within the receiver between an open position and a closed position. A pin extends through the receiver engaging a camming groove in the bolt to guide and lock the bolt against a primer end of an ignition casing. The camming groove and metal pin are configured to compress a face of the ignition cartridge against the breech plug when the bolt is in the closed position.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

FIELD OF THE INVENTION

This disclosure relates to bolt action muzzle loading firearms.

BACKGROUND OF THE INVENTION

Muzzle loading firearms, in which the projectile and the propellant charge are loaded from the muzzle end of the barrel, have become increasingly popular due in part to the establishment of special muzzle loader only seasons in many states.
In-line bolt action muzzle loading firearms are particularly popular with hunters and firearms enthusiasts that prefer a modern configuration. A significant example of such firearms is disclosed in my prior U.S. Pat. Nos. 5,706,598 and 6,385,887, which are hereby incorporated by reference in their entireties herein. These patents describe an adaptor or breech plug for mounting a cartridge casing that is used to convert a standard cartridge firing firearm into a muzzle loading firearm. A cartridge case with a primer, but without a bullet or propellant, is placed into the breech and the bolt closed to lock the cartridge into place. In each of my patents, it is described that the bolt is provided with camming lugs on the bolt adjacent the breech end to lock the bolt in the receiver. In order to accommodate the camming lugs at the breech end of the bolt, the receiver must have channels or raceways configured for receiving the camming lugs. Considerable machining is required to provide the raceways or channels for camming locks. A problem is that it is possible to convert the firearm to be a modern breech loading firearm by replacing the barrel. The present invention prevents this possibility.
Various other inserts and adapters with a nipple have been used to convert a cartridge gun into a black powder muzzle loading firearm using a percussion primer cup. The cap is small and difficult to place on the nipple, and various muzzle loading firearms that do not use a primed cartridge casing for igniting the projectile propellant are described in the literature.

SUMMARY OF THE DISCLOSURE

Disclosed is a muzzle loading, bolt action firearm with a receiver and a barrel into which a propellant and bullet is introduced through the muzzle, which comprises: (a) a bolt assembly with a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge casing, and a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; (b) a handle mounted on the bolt body adapted to longitudinally slide the body along a mating cylindrical opening in the receiver, wherein the slot with the guide pin is adapted to guide the bolt body in the receiver to move the bolt along the axis until the face engages the head of the cartridge casing, and rotate the body on the axis into a locked position in the receiver, and wherein when the bolt body is rotated by the arm in the receiver, the bolt face is configured to press an inside of the casing opposite the primer against a member with an opening into the barrel for igniting the propellant. In certain embodiments, the slot is rectangular in cross-section. In certain embodiments, the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot. In certain embodiments, the bolt has an area of milled off lugs adjacent the face of the bolt. In certain embodiments, the bolt has a substantially constant cross-sectional shape at an area adjacent the face of the bolt. In certain embodiments, the pin is hardened steel.
Further, disclosed is a bolt and receiver assembly adapted for a muzzle loading, bolt action firearm with a barrel mounted on the receiver into which a propellant and bullet is introduced through the muzzle, which comprises: (a) a bolt assembly with a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge casing, with a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; (b) a handle mounted on the bolt body adapted to longitudinally slide the body along a mating cylindrical opening in the receiver, wherein the slot with the guide pin is adapted to guide the bolt body in the receiver to move the bolt along the axis until the face engages the head of the cartridge casing and rotate the body on the axis into a locked position in the receiver, and wherein when the bolt body is rotated by the arm in the receiver, the bolt face is configured to press an inside of the casing opposite the primer against a member with an opening into the barrel for igniting the propellant. In certain embodiments, the slot is rectangular in cross-section. In certain embodiments, the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot. In certain embodiments, the bolt has an area of milled off lugs adjacent the face of the bolt. In certain embodiments, the bolt has a substantially constant cross-sectional shape at an area adjacent the face of the bolt. In certain embodiments, the pin is hardened steel.
Further still, disclosed is a bolt assembly adapted for a muzzle loading, bolt action firearm with a receiver and a barrel into which a propellant and bullet is introduced through the muzzle, which comprises: (a) a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge casing, with a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; (b) a handle mounted on the bolt body adapted to longitudinally slide the body along a mating cylindrical opening in the receiver, wherein the slot with the guide pin is adapted to guide the bolt body in the receiver to move the bolt along the axis until the face engages the head of the cartridge casing and to rotate the body on the axis into a locked position in the receiver, and wherein when the bolt body is rotated by the arm in the receiver the bolt face is configured to press an inside of the casing opposite the primer against a member with an opening into the barrel for igniting the propellant. In certain embodiments, the slot is rectangular in cross-section. In certain embodiments, the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot. In certain embodiments, the bolt has an area of milled off lugs adjacent the face of the bolt. In certain embodiments, the bolt has a substantially constant cross-sectional shape at an area adjacent the face of the bolt.
Finally, disclosed is a muzzle loading bolt action firearm having a firing pin mechanism, comprising: a barrel having a breech end and a center bore along a longitudinal axis; a receiver mounted on the breech end of the barrel; a breech plug with an orifice along the axis located at the breech end of the barrel with an opening for a cartridge casing; an insert integral with or attached to the breech plug for sealingly engaging against a primer opening inside a cartridge case, the breech plug and the insert together defining a bore to allow a flame from an ignited primer to travel to a projectile propellant at the breech end of the barrel, and to provide a seal between the receiver and the barrel; a substantially cylindrical bolt aligned with the longitudinal axis without radially projecting the lug that is recipricatable and partially rotatable within the receiver between an open position in which the breech end of the barrel is accessible for loading or removing the cartridge casing and a closed position in which an end of the bolt can compressibly engage against the casing adjacent the primer cartridge, the bolt having a camming groove with a first section that extends longitudinally parallel to the axis and a second section that extends at an angle from a rearward end of the first section; and a pin that extends through a wall of the receiver and engages the camming groove to guide the bolt and lock the bolt against the primer at the face end of the ignition casing when it is loaded into the receiver, the camming groove and the metal pin configure to compress the face end of the ignition casing against the breech plug when the bolt is rotated into the closed position. In certain embodiments, the pin is threaded to facilitate removal of the pin from the receiver and for removal of the bolt from the receiver. In certain embodiments, the breech plug includes external threads and the breech end of the barrel includes internal threads engagable with the external threads of the breech plug.
Disclosed is a bolt and receiver dedicated muzzle loading, bolt action firearm that utilizes a modern configuration.
The muzzle loading firearm can employ a greatly modified cartridge bolt receiver without locking lugs that would normally project radially from the bolt adjacent the breech or forward end of the bolt, and a bolt that does not have locking lugs projecting from the forward end of the bolt. The absence of locking lugs and preferably raceways for the locking lugs prevents the firearm from being easily converted from a muzzle loading firearm into a center fire firearm. Without locking lugs on the bolt, and channels in the receiver for receiving the locking lugs, the bolt would not have sufficient locking strength to withstand the pressure from a modern cartridge. In a muzzle loading firearm, the pressure generated by the projectile propellant during firing is kept forward of the barrel breech by the breech plug, and thus locking lugs are not required. It would require a new bolt with locking lugs and a receiver with raceways to convert the muzzle loading firearm into a center fire firearm.
In certain embodiments, the muzzle loading firearm has a barrel having a breech end and a center bore, a receiver at the breech end of the barrel, and a breech plug located at the breech end of the barrel. An insert integral with or attached to the breech plug is provided for sealingly engaging against a primer opening in a cartridge case. The breech plug and insert together define a bore that allows a flame from an ignited primer inside the cartridge case to travel through the insert to a projectile propellant located at the breech end of the barrel forward of the breech plug. The breech plug and insert together also provide a seal for the barrel with the cartridge case.
The bolt that is substantially cylindrical without radially projecting lugs is recipricatable and partially rotatable within the receiver between an open position in which the breech end of the barrel is accessible for loading or removing the cartridge casing and a closed position in which an end of the bolt can compressibly engage against a primed cartridge case. The bolt includes a groove with a first section that extends longitudinally along the longitudinal axis and a second section that extends arcuately at an angle from a rearward end of the first section as a continuous channel. A pin extends through a wall of the receiver and engages the groove to move the bolt and lock the bolt to be compressed against a primer end of the ignition casing when the casing is loaded into the receiver. The ramming groove and metal pin are configured to compress a face end of the ignition cartridge casing against the insert inside face of a cartridge case when the bolt is rotated into the closed position.
The pin can be threaded to facilitate removal of the pin and the bolt from the receiver. The diameter of the bore extending through the insert can be substantially the same as a diameter of an opening in a head of a cartridge casing adjacent a primer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a barrel and action for the muzzle loading firearm with a longitudinal axis A-A.

FIG. 1A is an elevational view of the breech end of the cartridge shown in FIG. 1.

FIG. 1B is a cross-sectional view of the cartridge shown in FIG. 1.

FIG. 2 is a vertical cross-sectional view of the barrel and part of the action shown in FIG. 1.

FIG. 3 is a perspective view of the new bolt used in the receiver.

FIG. 3A is a cross-sectional view of the bolt shown in FIG. 3.

FIG. 4 is a perspective view of the barrel and action shown in FIG. 1.

FIG. 5 is a vertical cross-sectional view of the barrel and part of the bolt and receiver action shown in FIG. 1, with the bolt in the closed position, ready for firing.

FIG. 6 is a vertical cross-sectional view of the barrel and action shown in FIG. 1, with the bolt in the closed position and the firing pin engaged with a primer in the cartridge casing to ignite the powder in the barrel.

FIG. 7 is a perspective view of a breech plug and insert mounted in the breech end of the barrel.

FIG. 8 is a side view of the barrel and the breech plug illustrating how the breech plug is installed in the barrel.

FIG. 9 is an end view as seen along view lines B-B of FIG. 8.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

A barrel 10 having center bore 11 along axis A-A and action 12 for the muzzle loading firearm is shown in FIGS. 1 and 2. Firing action 12 includes barrel 10, a receiver 18, a trigger mechanism 14, a bolt action 15 and safety 14A. The trigger mechanism 14, safety 14A and barrel 10 may be of any suitable design, examples of which are commercially available. Bolt 15 carrying a firing pin mechanism 50 is mounted in receiver 18 for reciprocating movement in a direction substantially aligned with the longitudinal axis A-A of barrel 10. Firing pin 50 can be generally any suitable design, such as those customarily employed in center fire rifles. Bolt 15 functions to lock a cartridge casing 19 in position against an insert 34 (shown in FIG. 2). Mounted generally between barrel 10 and receiver 18 is a recoil lug 20 for transferring recoil from the action to the stock (not shown).
As illustrated in FIGS. 3 and 4, bolt 15 is removably retained and guided in receiver 18 by a guide pin 22 (e.g., a removable threaded screw which is hardened to the same standards as the receiver 18) that engages a camming groove 24. Guide pin 22 can, for example, have a hexagonal recess 22A for receiving a tool (e.g., an Allen wrench). Groove 24 includes a first section 25 that extends longitudinally along bolt 15 and a second section 26 that extends at a radial angle from the rearward end of the first section 25 of the groove 24 in a direction that is generally opposite to the direction that handle 46 extends from bolt 15 (see FIGS. 3 and 4). The angle and radius of the curved transition 30 from the first section 25 of the groove 24 to the second section 26 of groove 24 are configured with pin 22 to compress a cartridge case head 32 (FIG. 5) between a forward face or front end 15A of bolt 15 and an insert 34 mounted in a center bore 36 (see FIG. 7) of breech plug 16. Removal of bolt 15 from receiver 18 by removing guide pin 22 facilitates cleaning of the bolt 15 and receiver 18.
As shown in FIG. 8, breech plug 16 has external threads 38 to facilitate engagement with internal threads 40 inside barrel 10 (see FIG. 2) and allow breech plug 16 to be sealingly engaged with barrel 10 in use and removable as desired for cleaning or unplugging barrel 10. External barrel threads 45 are used to mount barrel 10 onto receiver 18 with recoil lug 20 disposed in a groove defined between barrel 10 and receiver 18. In addition to transferring recoil to the stock, recoil lug 20 can include means for positioning the firing action 12 on a gun stock (not shown) and/or securing the firing action 12 to a gun stock. Breech plug 16 includes an insert 34 having walls 42 defining a hexagonal cross-section that can be engaged by a socket wrench to facilitate installation of breech plug 16 into barrel 10 and removal of breech plug 16 from barrel 10 as needed or desired. Other configurations and tools may be used as desired.
As shown in FIG. 3, bolt 15 is substantially cylindrical in shape and has a substantially constant cross-sectional shape along its length, including an area adjacent the face of the bolt (forward end), deviating significantly only adjacent the cocking extension 44 where bolt handle 46 projects laterally. Because bolt 15 does not have locking lugs or any other features projecting radially adjacent to forward end 15A of bolt 15, receiver 18 preferably does not need raceways for receiving lugs that would normally project from the bolt 15 of a center fire rifle.
As can be seen in FIGS. 5 and 6, in the firing position, the rearward end 34A of insert 34 is sealingly pressed up against a center opening in head 32 of cartridge casing 19 so that upon actuating trigger mechanism 14, firing pin 50 is released from the position shown in FIG. 5 and forcefully impacts a primer 52 held in an opening 19A at the head 32 of cartridge 19, causing a flame or spark to rapidly travel through a narrow bore 54 extending through insert 34 to projectile propellant 56, igniting propellant 56 and causing explosive combustion of the propellant 56 and a rapid generation of high pressure gases which propel projectile 58 from the muzzle of barrel 10. In the illustrated embodiment, shown in FIGS. 2, 5 and 6, three black powder propellant pellets 56 are shown for propelling a conical bullet projectile 58. Loose powder can also be packed into the breech of the barrel with a ramrod as described in my U.S. Pat. No. 5,706,598. Each of the illustrated propellant pellets 56 includes a center bore 62 that provides an extended passageway for a flame or spark travelling through bore 54 of insert 34 to continue rapidly travelling through propellants 56, allowing substantially simultaneous explosive combustion of all propellants 56, and rapid development of very high pressures to allow development of higher projectile velocities upon firing than what could otherwise be achieved, such as with packed black powder. However, other types of propellants, amounts of propellant, and types of projectiles, such as patched round balls, may be used. In the illustrated embodiment shown in FIGS. 5 and 6, the projectile is saboted. Sabot 60 can be self-lubricating to facilitate loading of projectile 58.
Insert 34 can be integral with breech plug 16 (e.g., permanently affixed), or insert 34 can be removably attached to breech plug 16, such as with interlocking threads.
Referring to FIGS. 1 and 2, in use, the propellant 56 is loaded into the barrel 10 adjacent to the insert 34 using a ramrod (not shown). Then the cartridge casing 19 is inserted adjacent the insert 34, and bolt 15 is slid in receiver 18 so that forward face 15A engages the casing 19 and pushes it onto the insert 34 so that face 15A of the bolt 15 presses the opening 19A against the rearward end 34A of insert 34. The movement of the bolt 15 locks the firing pin 50 back, compressing spring 50A into a position in which the firearm is ready to be fired. Trigger 14B is squeezed so that the firing pin 50 slides down and impacts primer 52 igniting the propellant 56 in the barrel 10 and driving projectile (e.g., bullet) 58 out of the barrel 10.
While the illustrated embodiment is in a rifle or long gun format, the principles and physical structures described herein are adaptable to various other firearms, including pistols.
The various components of the muzzle loading firearm can be fabricated from any suitable steels, such as those materials that are conventionally employed in the manufacture of rifles. However, because breech plug 16 isolates receiver 18 from the high pressures developed in barrel 10 during firing of the firearm, cartridge casing 19 need not necessarily be made of brass, but instead could be made of a plastic material (a thermoplastic or thermoset polymeric material), a ceramic material, other metals (such as steel or aluminum), or other materials. Additionally, because the cartridge casing does not need to expand and seal against the walls of the receiver during firing, cartridge 19 can have a shape that is not necessarily cylindrical.
The design of the firing action 12 facilitates production of an extremely safe muzzle loading, bolt action firearm employing a primed cartridge casing 19 to ignite a propellant 56 and discharge a projectile 58 from the muzzle end of barrel 10. The design includes a bolt 15, a cartridge chamber defined in a portion of receiver 18, a breech plug 16 and insert 34 that cooperatively function to hold primed cartridge casing 19 in a protected area wherein the extremely high gas pressures that can be developed during explosive combustion of propellant 56 are safely contained and directed substantially entirely through the muzzle end of barrel 10 by compressing cartridge casing 19 between forward face 15A of bolt 15 and rearward or breech end 34A of insert 34. Unlike a conventional bolt action firearm using a primed cartridge to ignite the propellant, whether a muzzle loading firearm or a center loading firearm, wherein the bolt has a longitudinal slot that is used primarily for guiding the bolt within the receiver and locking lugs are used for locking the cartridge in a cartridge chamber of the receiver, the novel firearm disclosed herein eliminates the conventional locking lugs used with primed cartridges and instead employs a groove 24 on bolt 15, which in combination with guide pin 22 serves both the guiding function of a conventional longitudinal bolt slot, while also functioning to lock the primed cartridge casing in a cartridge chamber of the receiver so that the cartridge casing is securely compressed between a forward end or face 15A of bolt 15 and a rearward end 34A of insert 34. The locking action is achieved without locking lugs by employing very precise dimensional tolerances in the various components, and in particular bolt 15 has a groove 24 with a transition portion 30 that is precisely designed to employ a camming action with pin 22 to securely lock primed cartridge casing 19 in a proper position for firing. Additionally, breech plug 16 and insert 34 are designed to direct a flame or spark from the primer in the cartridge through a narrow bore 54 that allows the flame or spark to ignite propellant 56, but which is sufficiently narrow to restrict the development of high back pressures in receiver 18. This combination of features makes it possible to employ a primed cartridge casing for igniting a propellant and discharging a projectile from a muzzle loading firearm without requiring locking lugs and, therefore, without requiring raceways machined into the receiver for the locking lugs. By eliminating the locking lugs and raceways for the lugs, that are conventionally employed for bolt action firearms using a primed cartridge to ignite the projectile propellant, it becomes impractical and nearly impossible to convert the firearm for use as a centerfire rifle, as this would require, at minimum, removal of breech plug 16 and insert 34 from barrel 10, replacement of bolt 15 with a bolt having locking lugs that are needed to contain the high back pressure developed in a receiver when the breech end of the barrel is open, and substantial machining of the receiver to provide raceways for the locking lugs.
In addition to providing a muzzle loading, bolt action firearm that is extremely safe to use, while facilitating very high projectile velocities and accurate shooting, and preventing easy modification for use as a centerfire rifle, the disclosed firearm can be configured as illustrated to facilitate easy disassembly and reassembly for cleaning and/or to remove blockages in the field, at a remote location, such as during hunting, using only easily portable hand tools, such as an Allen wrench to remove pin 22 and bolt 15, and a socket wrench to remove and/or install breech plug 16 and insert 34.
This combination of convenience, safety and dedication to muzzle loading, rather than convertibility to center loading, was not previously known or imagined, thereby providing a unique firearm with significant advantages over previously known muzzle loading firearms, including those disclosed in my previous patents.
Many modifications and variations of the present disclosure are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present disclosure may be practiced other than as specifically described.

Claims

What is claimed:

1. A muzzle loading, bolt action firearm with a receiver and a barrel into which a propellant and bullet is introduced through the muzzle, which comprises:

(a) a bolt assembly with a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge case, with a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; and

(b) a handle mounted on the bolt body adapted to longitudinally slide the body along a mating cylindrical opening in the receiver, wherein the slot with the guide pin is adapted to guide the bolt body in the receiver to move the bolt along the axis until the face engages the head of the cartridge casing and to rotate the body on the axis into a locked position in the receiver, and wherein when the bolt body is rotated by the arm in the receiver the bolt face is configured to press an inside of the casing opposite the primer against a member with an opening into the barrel for igniting the propellant.

2. The firearm of claim 1 wherein the slot is rectangular in cross-section.

3. The firearm of claim 1 wherein the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot.

4. The firearm of claim 1 wherein the bolt has a substantially constant cross-sectional shape at different locations along the length of the bolt at a section adjacent the face of the bolt.

5. The firearm of claim 1 wherein the bolt has an area of milled off lugs adjacent the face of the bolt.

6. The firearm of claim 1 wherein the pin is hardened steel.

7. A bolt and receiver assembly adapted for a muzzle loading, bolt action firearm with a barrel mounted on the receiver into which a propellant and bullet is introduced through the muzzle, which comprises:

(a) a bolt assembly with a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge casing, with a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; and

(b) a handle mounted on the bolt body adapted to longitudinally slide the body along a mating cylindrical opening in the receiver, wherein the slot with the guide pin is adapted to guide the bolt body in the receiver to move the bolt along the axis until the face engages the head of the cartridge casing and to rotate the body on the axis into a locked position in the receiver and wherein when the bolt body is rotated by the arm in the receiver the bolt face is configured to press an inside of the casing opposite the primer against a member with an opening into the barrel for igniting the propellant.

8. The bolt and receiver assembly of claim 7 wherein the slot is rectangular in cross-section.

9. The bolt and receiver assembly of claim 7 wherein the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot.

10. The bolt and receiver assembly of claim 7 wherein the bolt has a substantially constant cross-sectional shape at different locations along the length of the bolt at a section adjacent the face of the bolt.

11. The bolt and receiver assembly of claim 7, wherein the bolt has an area of milled off lugs adjacent the face of the bolt.

12. The bolt and receiver assembly of claim 7 wherein the pin is hardened steel.

13. A bolt assembly adapted for a muzzle loading, bolt action firearm with a receiver and a barrel into which a propellant and bullet is introduced through the muzzle, which comprises:

(a) a cylindrical bolt body defining a longitudinal axis, with a cross-sectional diameter along the axis from a distal end to a proximal end, with a face at the proximal end adapted for engaging a head of a primed cartridge casing, with a longitudinal slot along a surface of the body adapted to engage a guide pin on the receiver, and with a spring loaded firing pin adapted to selectively engage the primer on the cartridge casing when released by a sear activated by a trigger on the firearm; and

14. The bolt assembly of claim 13 wherein the slot is rectangular in cross-section.

15. The bolt assembly of claim 13 wherein the slot is angled adjacent the handle towards the face of the bolt and the pin on the receiver is positioned to mate with the slot.

16. The bolt assembly of claim 13 wherein the bolt has a substantially constant cross-sectional shape at different locations along the length of the bolt at a section adjacent the face of the bolt.

17. The bolt assembly of claim 13 wherein the bolt has an area of milled off lugs adjacent the face of the bolt.

18. The bolt assembly of claim 13 wherein the pin is hardened steel.

19. A muzzle loading, bolt action firearm having a firing pin mechanism, comprising:

a barrel having a breech end and a center bore along a longitudinal axis;

a receiver mounted on the breech end of the barrel;

a breech plug with an orifice along the axis located at the breech end of the barrel with an opening for a cartridge casing;

an insert integral with or attached to the breech plug for sealingly engaging against a primer opening of a cartridge case, the breech plug defining a bore to allow a flame from an ignited primer to travel to a projectile propellant at the breech end of the barrel;

a substantially cylindrical bolt aligned with the longitudinal axis without radially projecting lugs, that is recipricatable and partially rotatable within the receiver between an open position in which the breech end of the barrel is accessible for loading or removing the cartridge casing and a closed position in which an end of the bolt can compressibly engage against the casing adjacent the primer cartridge, the bolt having a camming groove with a first section that extends longitudinally parallel to the axis and a second section that extends at an angle from a rearward end of the first section; and

a pin that extends through a wall of the receiver and engages the caroming groove to guide the bolt and lock the bolt against the primer at the face end of the ignition casing when it is loaded into the receiver, the camming groove and the metal pin configured to compress the face end of the ignition casing against the breech plug when the bolt is rotated into the closed position.

20. The muzzle loading firearm of claim 19, wherein the pin is threaded to facilitate removal of the pin and from the receiver and for removal of the bolt from the receiver.

21. The muzzle loading firearm of claim 19, wherein the breech plug includes external threads and the breech end of the barrel includes internal threads engagable with the external threads of the breech plug.