US-20260126257-A1 - RIFLE WITH TAPERED INTERFACES

Abstract

A rifle with tapered interfaces has a receiver, a barrel extension connected to the receiver at a first interface, a barrel connected to the barrel extension at a second interface, a barrel nut element connected to the barrel extension at a third interface and to the barrel at a fourth interface, and at least two of the first, second, third, and fourth interfaces being tapered interfaces. The tapered interfaces may be stably tapered such that a wedging effect is generated. The barrel extension may have two tapered interfaces. The barrel extension may have a forward external tapered interface connecting to the barrel nut element and a forward internal tapered interface connecting to the barrel.

Inventors

• Thomas Afshari

Assignees

• 03312004 LLC

Dates

Publication Date

20260507

Application Date

20251217

Claims (1)

1. 1 . A firearm comprising: a receiver; a barrel extension connected to the receiver at a first interface; a barrel connected to the barrel extension at a second interface; a barrel nut element connected to the barrel extension at a third interface; the barrel nut element connected to the barrel at a fourth interface; and at least three of the first, second, third, and fourth interfaces being tapered interfaces.

Description

CLAIM OF DOMESTIC PRIORITY The present application is a Continuation of U.S. application Ser. No. 18/544,736, filed Dec. 19, 2023, entitled RIFLE WITH TAPERED INTERFACES, which is a Continuation-in-Part of U.S. application Ser. No. 17/662,994, filed May 11, 2022, which claims the benefit of U.S. Provisional Application No. 63/265,701, filed Dec. 20, 2021, which applications are incorporated herein by reference. The present application also claims the benefit of U.S. Provisional Application No. 63/436,895, filed Jan. 4, 2023, which application is incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to firearms, and more particularly to a rifle with tapered interfaces that enables the barrel of a rifle to remained centered relative to the receiver bore during thermal expansion of the rifle's components. BACKGROUND Modern firearms are designed and manufactured to operate with multiple inter-operational components and often with modular construction. In one example, an AR-10 or AR-15 style sporting rifle 100 uses a modular construction with an upper receiver 102 and lower receiver 104, as shown in FIG. 1a. Lower receiver 104 is characterized by trigger guard 106, trigger assembly 108, pistol grip 110, and magazine well 112. Buttstock 114 attaches to lower receiver 104. Upper receiver 102 is characterized by bolt carrier assembly, forward assist, charging handle, and gas-operated reloader. Ejector 118 provides for exit of spent cartridges from upper receiver 102. Barrel assembly 120 with handguard 122 attaches to upper receiver 102. Lower receiver 104 is attached to upper receiver 102 by removable rear take-down pin 124 and forward pivot pin 126. Removing rear take-down pin 124 allows upper receiver 102 to hinge and rotate about forward pivot pin 126, see FIG. 1b. Barrel assembly 120 is typically secured to upper receiver 102 with a single barrel nut. The barrel nut torques the barrel to upper receiver 102. Unfortunately, the single barrel nut does not ensure, and generally does not provide, proper alignment between the bore of the barrel and the bore of upper receiver 102. Any misalignment between the bore of the barrel and the bore of upper receiver 102 can cause wear on the bolt, catastrophic failure of the bolt, and un-torquing of the barrel extension due to vibration and heat expansion. Moreover, even when the barrel is properly secured to the upper receiver via the barrel nut and barrel extension, the ignition of ammunition inside the barrel chamber still can cause the length of the barrel to move, i.e., “whip,” due to harmonic vibration. The harmonic vibration decreases the reliability and accuracy of the barrel. A standard barrel mounting system for the AR platform relies on flat torque shoulders to mount the barrel to the barrel extension, to fit the barrel extension to the upper receiver, and to secure the entire system onto the upper receiver via a singular barrel nut. These torque shoulders are typically not perfectly flat and exhibit high points and low points, even if only by a few thousandths of an inch. The effect of this is that upon installation, the barrel bore may not sit center with the upper receiver bore, and the barrel muzzle may lean away from the upper receiver axis. Any trauma to the barrel or handguard can then cause the barrel to further move away from center and alignment because of the lack of secure and even contact points. This degrades the rifle's accuracy. Moreover, the barrel, barrel extension, upper receiver, and barrel nut are all typically machined from different metals, each with their own thermal expansion rate. When the weapon is fired and its component materials heat up at different rates, the barrel deviations from center and alignment can be exacerbated. This further degrades the rifle's accuracy, particularly during prolonged shooting, and results in a need to frequently re-zero the weapon. Manufacturers have attempted to solve this problem by a process known as shrink-fitting or thermal fitting, which is under-sizing the internal diameter of the upper receiver (i.e., machining it smaller) and over-sizing the outer diameter of the barrel extension (i.e., machining it larger) to the point where they will not fit together, and then using heat to force the installation. More specifically, the manufacturer will heat up (and consequently enlarge) the aluminum upper receiver, insert the steel or stainless-steel barrel extension, and then allow the upper receiver to cool and consequently contract around the barrel extension. The parts are then further secured by the barrel nut. The idea is that the thermal fit process is more rigid and secure than components torqued on flat shoulders, and the thermal fit process therefore makes the rifle more accurate both out of the box and over time. The problem with the above approach is the same thermal forces that are used to shrink-fit or thermal fit the parts are present during the normal operation o