Firearms – Breech loading – Sliding breechblock
Reexamination Certificate
1999-03-17
2001-04-03
Carone, Michael J. (Department: 3641)
Firearms
Breech loading
Sliding breechblock
C042S025000, C042S016000
Reexamination Certificate
active
06209249
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is a bolt for a bolt action rifle having front and rear bosses with a diameter slightly larger than the rest of the bolt body, thereby allowing for a tighter tolerance between the bolt and bolt runway, and improving accuracy.
2. Description of the Related Art
Bolt action rifles have existed since the later part of the nineteenth century. Although other action types have been developed, frequently offering greater speed for following shots, bolt actions remain popular for their unequalled reputation for strength and accuracy. Their widespread use has led many inventors to propose various ways to improve their overall operation and accuracy. Additionally, the reciprocating member of other action types has come to be known as a “bolt,” and some improvements to these actions is discussed below.
Although present bolt action rifles are highly regarded for their accuracy potential, they are not without room for improvement. Standard bolts have a uniform diameter over the entire length of their body, with the exception of the locking lugs in front and the bolt handle in the rear. The clearance between a standard bolt and the bolt runway is a compromise between accuracy, which is achieved by reducing the clearance, and smooth operation of the bolt, which is achieved by increasing the clearance to prevent foreign particles from binding the bolt. The present invention addresses both issues by providing a bolt having a front and rear boss with a slightly larger diameter than the bolt body, thereby allowing for a tighter tolerance between the bolt and bolt runway without causing the bolt to bind.
An early example of a rifle having a bolt is U.S. Pat. No. 36,852, issued to John C. Nye on Nov. 4, 1862, which describes a breech-loading firearm. The firearm includes a sliding bolt held in place by a hinged latch passing through both a hole in the barrel and a corresponding hole in the bolt.
U.S. Pat. No. 1,198,380, issued to Grant Hammond on Sep. 12, 1916, describes a breech bolt for firearms. The bolt includes top and bottom lugs in front, an ejector channel, and an extractor. A handle is located at the rear of the bolt. The bolt is operated by lifting the handle upward, and then pulling it rearward to open the breech. Pushing the bolt handle forward and then downward closes the breech.
At least two inventors have proposed safety improvements for bolt action rifles. U.S. Pat. No. 2,159,485, issued to Crawford C. Loomis on May 23, 1939, describes a bolt action rifle having a bolt with a cocking handle and striker connected by a spring. A blow to the cocking handle will therefore be softened before being transmitted to the striker, thereby reducing the possibility of accidental discharge. Additionally, U.S. Pat. No. 3,631,620, issued to Banri Ohira on Jan. 4, 1972, describes a bolt wherein the sear and cocking piece are not in contact when the bolt is unlocked, but are brought into contact only when the bolt is completely locked.
U.S. Pat. No. 3,710,492, issued to Frank B. Tirrell on Jan. 16, 1973, describes a travel guide for bolt action rifles. The guide is located behind the locking lugs, and travels in a slot parallel to the direction of bolt travel. When the bolt is locked, the locking lugs are vertical and the travel guide remains horizontal. When the bolt is unlocked, the locking lugs are horizontal and in the same plane as the guide. One locking lug travels in a slot on the left side of the rifle, and the guide travels in a slot below the ejection port. This prevents binding of the bolt when the locking lug on the right side travels across the ejection port and can not be guided by a slot.
In addition to bolt actions, bolts for automatic and semiautomatic rifles have been the subject of inventive efforts. For example, U.S. Pat. No. 2,941,449, issued to Frederick P. Reed on Jun. 21, 1960, describes a decelerating device for firearms with telescoping bolts. The bolt includes a nonrotatable carrier and a rotatable head. The head includes a plurality of locking lugs. The head also includes a follower protruding through a diagonal slot on the carrier. As the bolt reaches the chamber, the locking lugs pass through a recess between a plurality of cam surfaces in the decelerator at the breech end of the barrel. When the head reaches its limit of travel, the carrier is still traveling forward. The follower within the carrier's diagonal slot causes the head to rotate so that the locking lugs engage the cam surfaces within the barrel. A similar invention is described in U.K. Pat. App. No. 2,207,493, filed by Sterling Armament Company Ltd. for an invention by Frank E. Waters and published on Feb. 1, 1989.
At least two inventors have proposed the use of lands and grooves on the exterior surface of a bolt for a semiautomatic or automatic rifle. U.S. Pat. No. 2,425,684, issued to George William Patchett on Aug. 12, 1947, describes a bolt having helical lands on its outside surface. The helical lands force foreign particles out the slot wherein the cocking handle travels. Additionally, U.S. Pat. No. 5,551,179, issued to Daniel H. Young on Sep. 3, 1996, describes a bolt carrier for an AR-15 or M-16 rifle having an increased number of lands and grooves. Mr. Young claims that the increased number of lands results in better bolt carrier alignment and better retention of lubricant.
Lastly, U.S. Pat. No. 2,861,374, issued to Samuel L. Hampton on Nov. 25, 1958, describes a bolt for a slide action rifle. The bolt includes a firing pin tube and three concentric sleeves, with the central sleeve having four inwardly biased fingers with locking heads on their front ends. The innermost sleeve is attached to the forestock sleeve. Pushing the forestock sleeve forward first moves the bolt forward, chambering a cartridge, and then pushes the inner sleeve against the central sleeve, thereby pushing the fingers outward and the locking heads into a groove within the rifle's receiver, locking the bolt in the closed position until the forearm sleeve is moved rearward.
No invention within the knowledge of the present inventor has addressed the problem of optimizing the firing accuracy of a bolt action rifle while preventing binding by providing increased diameter bosses at the front and rear of the bolt. None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a bolt for firearm allowing for reduced clearance between bolt and bolt runway solving the aforementioned problems is desired.
SUMMARY OF THE INVENTION
The invention is a bolt having an increased diameter at the rear section immediately in front of the handle, and at the front section immediately behind the locking lugs, hereinafter called a boss. These bosses allow for a tight tolerance between the bolt runway and the bolt, thereby increasing accuracy.
A standard bolt for a bolt action rifle has a body with a uniform diameter. The rear portion of the bolt includes a handle for operating the bolt, and the front portion includes locking lugs mating with the action adjacent to the barrel, for securing the bolt in place during firing. The locking lugs on a standard rifle may number 2, 3, 4, or even 9, and the present invention will function with any of the above numbers of lugs, or any other number. A firing pin assembly passes through the center of the bolt, and is brought into contact with the trigger mechanism of the firing pin when the bolt is fully closed and locked. The bolt may also include an extractor for hooking the rim of a cartridge case to extract it from the rifle's chamber, and/or an ejector for knocking a cartridge case out of the rifle during reciprocation of the bolt.
The rear boss is a section of the bolt body immediately in front of the bolt handle having a diameter slightly larger than the remainder of the bolt body. The rear boss has either a uniform or eccentric diameter, which is preferably less than or equal to 0.001 inch less than the diameter of the bolt runway, resulti
Carone Michael J.
Chambers Troy
Litman Richard C.
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