Ser. No. 16/252,639 Application Date: Jan. 20, 2019
The field relates to gunsmithing and, more specifically, to tools for assembly and disassembly of firearms and methods for their use.
Classification: B25B—B25B 27/00
Keywords: armorer, gunsmith, tool, block, support, mount, firearm
U.S. Pat. No. 9,849,566 B2 Dec. 26, 2017, William Bradley Bennet and others
U.S. Pat. No. 9,523,035 B2 Nov. 21, 2017, William H. Geissele and others
U.S. Pat. No. 9,372,041 B1 Jun. 21, 2016, William H. Geissele and others
A typical AR platform long-barreled firearm, see
The upper receiver configures the upper front end of the weapon and attaches the barrel (3), barrel nut (4), the gas system (not shown in the figures), the muzzle brake or flash hider (5), the modular handguard (6), the sight system that can be iron sights, a red dot or magnified scope (7), the charging handle (8), and an optional foregrip (9). The barrel is attached to the upper receiver with the barrel nut (4), see
The bolt carrier group (BCG) (16) and the buffer (not shown in the drawings) travel back and forth along the upper receiver cylindrical well (19), see
A description of the firearm barrel is necessary to clearly understand this assembly, the barrel always comes assembled with the barrel extension from the factory, through a thread, the barrel extension is tightened and pinned against the barrel itself, to the naked eye the barrel is one piece, the barrel nut (4) holds the barrel extension securely against the upper receiver (1), therefore the barrel (3) to the upper receiver (1).
In the firearm AR platform, installing or removing the barrel to the upper receiver to perform initial assembly, maintenance, parts replacement, or adjustment requires the application of torque to the barrel nut (4). Also, the application of torque is needed to perform similar operations with parts like the flash hider or muzzle brake (5). See
Also, torque is required to tighten the castle nut (17) to assemble the lower receiver (2) to the receiver extension or buffer tube (14). Currently, in the market, there are two variants for the receiver extension: the MILSPEC and the Commercial both can be used with the lower receivers for the AR-15 or the AR-10. See
One common problem associated with removal and mounting of such firearm parts and related components is for the torque applied during the removal or mounting actions to be transferred to other parts of the firearm with unwanted consequences like:
In another aspect of the art, currently most of the tools available are:
On the other hand, the current art accumulated cost of several tools necessary to cover most of the receivers available is only afforded by the professional gunsmith and the manufacturers themselves.
The popularity of the light recoil, reliable and accurate AR-15 and AR-10 platforms is unmatched. Since the original patent expired about 1980, the civilian model began to be mass produced by a variety of companies. The market took notice of its modular construction and soon new bullet calibers and configurations appeared to satisfied shooters all over America and the world. Today, in America an owner can have one lower receiver with multiple uppers, each configured for a different use, one strictly for plinking and fun, another for hunting deer, one for varmints or predators, one for self-defense, another for long range shooting competition, other for training, and even one chambered for the .22 Long Rifle cartridge or a 9 mm pistol round. This incredible versatility is the beauty of the AR platform allowing to personalize the rifle to suit the most demanding needs and tastes.
The AR rifle can be purchased as a fully assembled package, a gun kit, pre-assembled components, or even individual parts from a wide selection of aftermarket options.
Assembling near to 50 parts of a complete rifle is relatively easy. There are only two operations that are somehow demanding, they are the tightening of the barrel nut (4) and the castle nut (17), with a recommended torque, for assembly or otherwise releasing same parts for disassembling; they are the subject of the use of tools described in this patent.
The AR-15 and the AR-10 receivers share most of the functional features, the upper receiver of the AR-10 platform has larger overall dimensions than the AR-15, the bolt carrier well has a bigger diameter and it is longer than the AR-15 counterpart to accommodate the larger dimensions of the AR-10 bolt carrier group.
Also, the AR-10 and AR-15 lower receivers (2) share most of the functional features and use the same thread specification to receive the lower receiver extension (14). Although, there are two versions of receiver extensions compatible to both the AR-15 and the AR-10: the MIL-SPEC version and the Commercial version, the main difference between them is the choice of raw materials and the manufacturing processes that make the outside diameter and some externals features are slightly different.
In general terms, this disclosure is directed to armorer tools for distributing the torque associated with assembling and disassembling components of a firearm of the AR-15 and AR-10 platforms over a very wide surface. The two tools of the system disclosed in this patent attached to a bench vise would safely support the AR upper receiver (1) to tighten the barrel nut (4) to assemble the barrel (3) with the AR upper receiver, and the lower receiver extension (14) also called the buffer tube, to tighten the castle nut (17) to assemble the buffer tube with the lower receiver (2).
On the other hand, the tool system subject of this patent supports the whole range of AR platform configurations, and available parts in the market, reducing the need to have multiple tools making it more affordable to a wider range of professional armorers and DIY enthusiasts, and making possible to use a wider range of bullet specifications and calibers since they are barrel extension and magazine well geometry independent. Furthermore, they can be used with a wider selection of upper and lower receiver styles because they are independent of the external features of the receivers themselves.
The AR Armorer Tool System disclosed herein consists of two embodiments: The upper receiver support tool and the lower receiver extension support tool.
The upper receiver support tool, disclosed herein, is comprised by a bar having a substantially rectangular section (30) with a lengthwise recess in the front end (31) for the AR-15 and a wide rear end (32) for the AR-10. Small filling blocks (37) with a profile matching the AR-15 bolt carrier well are attached to the plate on the tool's front narrow end or large filling blocks (38) with a profile matching the AR-10 bolt carrier well attached on the tool's wide rear end.
The first embodiment is meant to tighten the barrel nut (4) and to be securely held by a bench press (50) to assemble the barrel (3) with the upper receiver (1) of the firearm. The upper receiver support tool can be used to hold both AR-15 and AR-10 upper receivers, as disclosed herein, configuring one end exclusively with the blocks matching the corresponding upper receiver type. See
Also, the upper receiver support tool can be used to tighten the muzzle brake or flash hider (5) against the barrel or to a counter nut used for the same purpose.
The lower receiver extension support tool, disclosed herein, is meant to tighten the castle nut (17) to assemble the lower receiver (2) with the lower receiver extension or buffer tube (14), the tool is capable to support both the MIL-SPEC and COMMERCIAL receiver extension versions.
The lower receiver extension support tool is comprised of two symmetrical blocks that when tightened together against the receiver extension by a bench vise are capable to hold the assembly securely to tighten the castle nut (17). See
By its nature, it is independent of the magwell specification and the receiver externals features and size, making possible to be used with all receivers in the market.
Also, the lower receiver support tool can be used as an aid to install or remove most of the receiver internal parts.
The First Embodiment of an armorer tool system, the upper receiver support tool, disclosed herein, is for the assembly primarily of the barrel and the upper receiver of the firearm, and secondary for the installation of the gas block, muzzle brake or flash hider and handguard, (each notable part has the same identifier number, refer to
The First Embodiment of the armorer tool system, disclosed herein, is meant to use the bolt carrier group and the charging handle wells (19 and 20), this is to use the internal features of the upper receiver to support the assembly. There are several tool configurations that can achieve this goal, for example, a couple of round bars with an integral or detachable key.
The selected configuration disclosed herein comprises a rectangular bar or elongated member, it has the positions of the blocks' holes on the bar configured such that the cylindrical sides of the blocks (37 and 38) when installing on the bar, are substantially concentric with the corresponding bolt carrier group well (19), see
In another aspect of the art, the First Embodiment of the armorer tool system, wherein by its nature, is independent from barrel extension making possible to be used with any type and caliber of barrel extension specification, and independent from the features and specifications of the externals of the upper receiver making possible to be used with any style, including custom upper receivers.
The First Embodiment of an armorer tool system, wherein the elongated member material is high strength aluminum or steel, the blocks material can be metallic, polymer or other suitable material. The manufacturing is a combination of sawing, machining, die cutting, drilling, tapping, forge, extrusion, injection molding, 3D-Printing or another suitable method.
Barrel Nut Tightening Method
The First Embodiment of an armorer tool system, wherein is configured to be used with AR-15 upper receivers attaching only the AR-15 bolt carrier group well blocks to the front end of the tool (37), two on each side, the corresponding blocks for the AR-10 receiver (38) are to be removed from the assembly. The rear end is to be securely attached to a bench vise (50). See
The First Embodiment of an armorer tool system, wherein is configured to be used with AR-10 upper receivers attaching only the AR-10 bolt carrier well blocks to the rear end of the tool (38), two on each side, the corresponding blocks for the AR-15 receiver are to be removed from the assembly (37). In this case, the front end is to be securely attached to a bench vise (50). See
The First Embodiment of an armorer tool system, wherein the upper receiver (1) is slid over the armorer tool through the bolt carrier well until the tool touches the end of the charging well and it is secured attaching a threaded pin through the spent cartridge ejection port of the corresponding upper receiver (34). See
The First Embodiment of an armorer tool system, wherein the barrel of the firearm (3) is to be introduced into the upper receiver and then the barrel nut (4) is threaded into the upper receiver corresponding thread. Then torque is applied to the barrel nut, either for assembling or disassembling. The torque is distributed over a very large area along the charging handle well and the bolt carrier well blocks. The recommended magnitude of this torque is between 40-80 foot-pounds. Other parts like the Gas Block, Muzzle Brake or Flash Hider and Handguard can be subsequently installed. See
Acting Forces and Stress
The free body diagram in
From the receiver perspective, the required area is six times smaller since the bearing Yield Strength of aluminum is 56,000 PSI, the resulting force of 1,920 lbs. it is distributed along the length of the receiver 5.5 inches, and requiring only 0.04 sq-in. along the charging handle well (20).
The Second Embodiment of an armorer tool system, disclosed herein, is primarily for the assembly of the lower receiver extension or buffer tube to the lower receiver of both the AR-15 and the AR-10 firearms.
And, secondarily to safely hold the lower receiver to install or disassemble the magazine release, trigger system, safety and bolt release small parts comprising, see
The Second Embodiment of an armorer tool system disclosed herein, is meant to use the lower receiver extension or buffer tube (14). Its purpose is to apply the available force in a bench vise jaw directly on the tool blocks, in turn, over the external features of the lower receiver extension to safely support the assembly; achieving a very simple, compact, light, safe, and effective support tool block set.
In another aspect of the art, the Second Embodiment of the armorer tool system, wherein by its nature, is independent from the magazine well geometry and, independent of the external specification of the lower receiver making possible to be used with lower receivers of any external features and magazine specification, size, caliber, shape, and form.
The Second embodiment of an armorer tool system wherein the lower receiver extension block is configured to match the two types of lower receiver extensions (14) the MIL-SPEC and the Commercial types. The block cylindrical radius and center position are set to match the diameter of 29.16 mm of the MIL-SPEC and the 29.68 mm of the Commercial types.
Small parts related to this assembly must be already installed according to the recommendations of their respective manufacturers: The Takedown Pin (51), Takedown Pin Detent (52), Takedown Pin Detent Spring (53), Buffer Retainer Pin (54), and Buffer Retainer Pin Spring (55). See
The Second embodiment of an armorer tool system wherein the angled member material is high strength aluminum or steel and the blocks material can be metallic, polymer or other suitable material. The manufacturing is a combination of sawing, die cutting, machining, drilling, tapping, forge, extrusion, injection molding, 3D-Printing or another suitable method.
Castle Nut Tightening Method
The Second embodiment of an armorer tool system, disclosed herein, is used to tighten or release the castle nut (17) that secures the receiver extension with the lower receiver, see
For cylindrical buffer receivers without the buttstock length adjustment key (23) will be necessary to apply extra force to keep the buffer tube stationary when the torque is applied. In this case, the user is responsible to avoid applying excessive force to permanently deform the buffer tube, particularly with skeletonized versions. Using a piece of sandpaper between the blocks and the buffer tube might add extra friction.
Acting Forces and Stress
The free body diagram in
From the receiver perspective, the required area is six times smaller since the bearing Yield strength of aluminum is 56,000 PSI, the resulting force of 800 lbs. it is distributed along the length of the receiver ˜1.5 inches spreading the load requiring only 0.015 sq-in.