Firearm bolt configured to prevent the firing of a conventional cartridge
A firearm configured to fire only a modified cartridge, while being unable to fire a conventional cartridge. The breech bolt in the inventive device includes an added geometric element that prevents the bolt closing on a conventional cartridge and which will only allow the bolt to close on a modified cartridge.
1. A firearm configured for use with a centerfire cartridge, said cartridge having a base, a central axis and a primer having a primer diameter located in said base and being aligned with said central axis, said firearm comprising:
a. a breech bolt, including a planar bolt face configured to mate against said base of said centerfire cartridge, wherein said bolt face includes a recess;
b. a firing pin aperture in said bolt face, said firing pin aperture housing a firing pin with a nose that is recessed behind said bolt face;
c. a ring protrusion extending forward from said bolt face and centered on said firing pin aperture, wherein said ring protrusion is part of an insert configured to fit within said recess in said bolt face;
d. said ring protrusion having a base and a tip; and
e. said ring protrusion narrowing from said base to said tip.
2. The firearm as recited in claim 1 , wherein said ring protrusion narrows from said base to said tip in a linear taper.
3. The firearm as recited in claim 2 , wherein:
a. said ring protrusion includes an inner angled wall and an outer angled wall; and
b. an angle between said inner angled wall and said outer angled wall is between 20 and 60 degrees.
4. The firearm as recited in claim 1 , wherein:
a. said ring protrusion includes an inner diameter and an outer diameter; and
b. said inner diameter is larger than said primer diameter.
5. The firearm as recited in claim 4 , wherein:
a. said breech bolt includes an extractor; and
b. said outer diameter is small enough to remain clear of said extractor.
6. The firearm as recited in claim 1 , wherein a distance between said base and said tip of said ring protrusion is between 1.7 mm and 5.0 mm.
7. A breech bolt for use in a firearm configured for use with a centerfire cartridge, said centerfire cartridge having a base, a central axis and a primer having a primer diameter located in said base and being aligned with said central axis, said breech bolt comprising:
a. a planar bolt face configured to mate against said base of said centerfire cartridge, wherein said bolt face includes a recess;
b. a firing pin aperture in said bolt face, said firing pin aperture housing a firing pin with a nose that is recessed behind said bolt face;
c. a ring protrusion extending forward from said bolt face and centered on said firing pin aperture, wherein said ring protrusion is part of an insert configured to fit within said recess in said bolt face;
d. said ring protrusion having a base and a tip; and
e. said ring protrusion narrowing from said base to said tip.
8. The breech bolt as recited in claim 7 , wherein said ring protrusion narrows from said base to said tip in a linear taper.
9. The breech bolt as recited in claim 8 , wherein:
a. said ring protrusion includes an inner angled wall and an outer angled wall; and
b. an angle between said inner angled wall and said outer angled wall is between 20 and 60 degrees.
10. The breech bolt as recited in claim 7 , wherein:
a. said ring protrusion includes an inner diameter and an outer diameter; and
b. said inner diameter is larger than said primer diameter.
11. The breech bolt as recited in claim 10 , wherein:
a. said breech bolt includes an extractor; and
b. said outer diameter is small enough to remain clear of said extractor.
12. The breech bolt as recited in claim 7 , wherein a distance between said base and said tip of said ring protrusion is between 1.7 mm and 5.0 mm.
13. A firearm configured for use with a centerfire cartridge, said centerfire cartridge having a base, a central axis and a primer having an outer primer diameter located in said base and being aligned with said central axis, comprising:
a. a breech bolt, including a bolt face configured to mate against said base of said centerfire cartridge, wherein said bolt face includes a recess;
b. a firing pin aperture in said bolt face, said firing pin aperture housing a firing pin with a nose that is recessed behind said bolt face;
c. a ring protrusion extending forward from said bolt face and centered on said firing pin aperture, wherein said ring protrusion is part of an insert configured to fit within said recess in said bolt face;
d. said ring protrusion having a base and a tip; and
e. said ring protrusion being wider at said base than said tip.
14. The firearm as recited in claim 13 , wherein said ring protrusion narrows from said base to said tip in a linear taper.
15. The firearm as recited in claim 14 , wherein:
a. said ring protrusion includes an inner angled wall and an outer angled wall; and
b. an angle between said inner angled wall and said outer angled walls is between 20 and 60 degrees.
16. The firearm as recited in claim 13 , wherein:
a. said ring protrusion includes an inner diameter and an outer diameter; and
b. said inner diameter is larger than said primer diameter.
17. The firearm as recited in claim 16 , wherein:
a. said breech bolt includes an extractor; and
b. said outer diameter is small enough to remain clear of said extractor.