SUPPRESSIBLE AND UNIVERSAL HANDGUN BARREL

Abstract

Provided is a replacement pistol barrel for reliable operation when suppressed and that will universally fit multiple versions of a handgun model.

Description

TECHNICAL FIELD

This invention relates to a barrel designed to allow its use interchangeably on multiple versions of a handgun platform and to allow reliable slide cycling when used with a sound suppressor without extra barrel length extension.

BACKGROUND

Sig Sauer (“Sig”) has produced a “modular” line of handguns that allow a single chassis to be used with a variety of grips and a variety of slide/barrel combinations. This allows the user to change both the size (length of barrel and length of grip) and caliber using just one chassis. The chassis is the “frame,” which is the serialized part considered to be the “firearm” under U.S. law. Thus, without purchasing an additional “firearm” the user can reconfigure the handgun in multiple ways.

Sig handgun models also come in multiple configurations. For example the Sig P320 is available in the “full size” (4.7″ barrel), “compact”/“carry” (3.9″ barrel), and “subcompact” (3.6″ barrel). Additionally, the military version of the Sig P320 (M17/M18) includes a loaded chamber indicator (“LCI”) which requires a rear portion of the barrel, above the chamber, to include a notch to accommodate the LCI. The Sig P250 is also available in similar multiple configurations. To a certain degree, there is modularity between the P250 and P320, but there is very limited interchangeability of barrels between configurations, even of the same model, without also changing the slide. So, despite this “modularity,” a change in caliber requires a change of not only the barrel (and magazine), but also of the slide. Across a model platform, the barrels and slide for different configurations and/or calibers utilize different dimensional specification for the barrel lock-up block (trunnion), which engages with the ejection port of the slide. This engagement keeps the barrel and breach face of the slide locked together and delays unlocking until the barrel tilts downward at the breach end, allowing the slide to retract.

“Conversion kits” (also called “Caliber X-Change Kits”) are available from Sig to facilitate modularity. These kits include a barrel, slide, and magazine (and may include another grip). But, because the slide is a significant cost portion of a “change kit,” it would be desirable to have a “universal” barrel design that would operate with any of the slides for that model/platform. Specifically, the height of the top surface of the barrel lock-up block is different for different configurations, so that there is operation-preventing interference between certain barrels and certain slides of different configurations, even within the same model/platform, as the barrel tilts to unlock and allow the slide to retract.

When a pistol is fired, the rearward recoil force (equal and opposite to the forward force of the projectile) pushes the cartridge case head against the breach face of the slide. Because the barrel and slide are “locked” together at this stage of the firing sequence, both the barrel and slide initially move to the rear together a limited distance. In designs relevant to the present invention, the barrel lugs provide an angled slot that engages with a locking block structure in the frame below the barrel axis, which forces the rear (chamber) end of the barrel downward as the barrel shifts to the rear. The rearward movement of the barrel stops when the lugs have fully engaged the locking block. That that point, the rear end of the barrel has moved downward enough to allow the slide to pass over the barrel and continue its rearward travel, separate of the barrel, to eject the empty case. The barrel is tilted relative to the slide and its in-battery orientation, with the forward end of the barrel slidingly supported by inner surfaces of an opening at the forward end of the slide. As the distance shortens between these forward slide surfaces and the pivot point of the lugs engaged with the locking block, the displaced angle of the barrel increases. This angle is steeper and more pronounced with shorter barrels, as compared to longer barrels.

Pistols with short barrels can experience operational irregularities when used with a noise suppressor (silencer). Noise suppressors also adsorb a significant about of recoil. That recoil force is harnessed to cycle the slide to eject and then chamber a new cartridge. In tilting barrel designs (by far the most common), the barrel remains locked with the slide, keeping the chamber closed, until both the barrel and slide have moved a predetermined distance to the rear. As described above, the downward movement (tilt) of the barrel that allows the slide to pass over the barrel once the barrel has reached it limit of rearward/downward travel. The timing of this unlocking relative to the remaining pressure within the barrel is critical to reliable operation. In certain barrel designs, it is the forward top edge of an enlarged trunnion portion surrounding the chamber that engages/disengages with the slide to lock the cartridge head against the breach face of the slide until it disengages and allows the slide to pass over the now-tipped barrel.

Some noise suppressors include a “Nielsen device” or recoil booster that helps assure sufficient recoil to cycle the slide. The operation of these devices is well known. Additionally, the effective length of the barrel may be increased beyond that necessary for threads (often by as much as an additional 0.5″) to extend beyond the slide when the barrel is intended for use with a suppressor. This extra length allows more propellant powder to burn and can help to increase the recoil to a level sufficient to cycle the slide when used with a suppressor.

SUMMARY OF THE INVENTION

The present invention provides a “universal” barrel design that will function with all slides across the Sig P320 platform and M17/M18 platform. A top, forward surface of the barrel portion surrounding the chamber is sloped and a rear notch is provided in the hood extension to receive a Loaded Chamber Indicator (LCI). If used with a slide that does not include an LCI and/or one that accepts a higher lock-up block top surface, the universal barrel will still function without any detrimental results. The width od the hood extension is reduced to the minimum dimension within tolerance specifications, allowing it to fit in all slide styles of a model.

By lowering the top forward edge that engages the slide to lock the barrel, the barrel will unlock at an earlier point in its cycle and while the barrel is at a less than fully angled position. The barrel is “fully angled” when its lugs have fully engaged the locking block of the frame and the slide has reached it full rearward recoil position.

Other aspects, features, benefits, and advantages of the present invention will become apparent to a person of skill in the art from the detailed description of various embodiments with reference to the accompanying drawing figures, all of which comprise part of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Like reference numerals are used to indicate like parts throughout the various drawing figures, wherein:

FIG. 1 is an isometric view from above and rear (right side) of a barrel according to an embodiment of the present invention;

FIG. 2 is a right side view thereof;

FIG. 3 is a rear end view thereof;

FIG. 4 is a top plan view of a first embodiment barrel in a locked-up position in a slide having a Loaded Chamber Indicator (LCI);

FIG. 5 is a side elevation view thereof;

FIG. 6 is a top plan view thereof with the barrel in an unlocked, partially tilted position at which the slide can pass;

FIG. 7 is a side sectional view thereof taken substantially along line 7-7 of FIG. 6;

FIG. 8 is a similar sectional view enlarged to show detail;

FIG. 9 is a top plan view of the barrel in a locked-up position in a slide not having an LCI; and

FIG. 10 is a side elevation view thereof.

DETAILED DESCRIPTION

With reference to the drawing figures, this section describes particular embodiments and their detailed construction and operation. Throughout the specification, reference to “one embodiment,” “an embodiment,” or “some embodiments” means that a particular described feature, structure, or characteristic may be included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the described features, structures, and characteristics may be combined in any suitable manner in one or more embodiments. In view of the disclosure herein, those skilled in the art will recognize that the various embodiments can be practiced without one or more of the specific details or with other methods, components, materials, or the like. In some instances, well-known structures, materials, or operations are not shown or not described in detail to avoid obscuring aspects of the embodiments. “Forward” will indicate the direction of the muzzle and the direction in which projectiles are fired, while “rearward” will indicate the opposite direction. “Lateral” or “transverse” indicates a side-to-side direction generally perpendicular to the axis of the barrel. Although firearms may be used in any orientation, “left” and “right” will generally indicate the sides according to the user's orientation when shooting; “top” or “up” will be the upward direction when the firearm is gripped in the ordinary manner.

Referring to the various drawing figures, and first to FIGS. 1-3, therein is shown a barrel 10 according to one embodiment of the present invention. The barrel 10 includes a chamber 12 at the breach end 14. The chamber 12 is coaxial with a rifled bore 16 which extends axially along the length of the barrel 10 to the muzzle 18 with external threads 19. The overall muzzle extension length L₁ does not need to be any greater than that necessary to accommodate the threads and to accept a muzzle device, such as a suppressor. Unlike, prior designs, the barrel 10 of the present invention does not need any extra extension in length. Other novel features of the barrel 10 cause the pistol to operate reliably when suppressed.

Substantially surrounding the chamber 12 is a squarish trunnion portion 20 that provides lock-up edges that engage with the ejection port of a slide (not shown in FIGS. 1-3). Lacking a formally accepted name, as used herein, “trunnion portion” of the barrel is used to refer to the blockish enlarged portion surrounding the chamber in pistol designs where this structure is used to engage with edges of the ejection port of the slide to lock the two parts together when in battery. Below the trunnion portion 20 are barrel lugs 22 that engage the locking block of the pistol frame (not shown in FIGS. 1-3), causing the breach end 14 of the barrel to tilt downward and unlock from the slide using blow-back forces produced by a fired cartridge in a well-known manner.

The trunnion portion 20 includes a top surface 24 that is usually configured to be, for example, even with an outer surface of the slide when engaged in the ejection port. At the upper breach end 14 of the trunnion portion 20, there is a hood extension 26 to support a portion of an ammunition cartridge (not shown) that may extend out of the chamber 12 when in battery. In configurations (such as the M17/M18) that include a Loaded Chamber Indicator (“LCI”), the hood extension 26 includes a notch 28 to accommodate the LCI. When the barrel 10 is used in a configuration that does not include an LCI, the cartridge remains adequately supported and the presence of the notch 28 causes no detrimental results.

The notch 28 may be substantially laterally centered and may be, for example, approximately 0.1300 inches in width (indicated at 30) and approximately 0.075 inches in axial depth (indicated at 32). The overall width W₁ of the hood portion 26 may be adjusted, as desired, to fit associated geometries of the slides. In preferred form, the width W₁ is selected to be at the minimum dimension within tolerance specifications, allowing it to fit in all slide styles of a model. This may be, for example, 0.395″ to 0.400″.

According to another aspect of this embodiment, the forward edge 34 of the top surface 24 of the barrel lock-up block 20 may be lowered relative to a rearward end of this surface 24. For example, the forward edge 34 may be lowered by approximately 0.020 inches so that at least a portion 36 of the top surface 24 is inclined. In the illustrated embodiment, this inclined area 36 may extend rearward from the forward edge 34 at least 0.275 inches (indicated at 37) an creating an angle of about 4.16 degrees declined from the horizontal top surface 24. If desired, the inclined area 36 could extend the full length of the top surface 24. It is the relative height of the forward edge 34 that is important to operation of the present invention. Accordingly, the inclined area 36 allows necessary clearance between the lock-up block 20 of the barrel 10 and the slide 38 as the slide retracts.

Referring now to FIGS. 4-7, therein the barrel 10 is shown in combination with a slide 38 having a Loaded Chamber Indicator (LCI) 40. When in battery (FIGS. 4 and 5), the LCI fits into the notch 28 in the hood extension 26. The barrel 10 is “locked” with the slide 38 by engagement of the trunnion portion with the ejection port 42 opening. Release of the lock-up is determined by the engagement between the top forward edge 34 of the trunnion portion 20 of the barrel 10 and the top forward edge 44 of the ejection port 42.

FIGS. 6, 7, and 8 show the barrel 10 partially tilted to the minimum angle (represented at 50) necessary to allow the slide 38 to move rearward past the barrel trunnion 20. The barrel is supported at two axially spaced apart pivot points: the locking block 46 and the inner opening surfaces 48 at the forward end of the slide 38. The locking block 46 of the frame is schematically illustrated in FIGS. 7 and 8 as being substantially circular in cross-section, although this structure often has other shapes. The exact shape of the locking block 46 structure is not important to the present invention and the drawing figures are intended to illustrate how the slide 38 can begin moving rearwardly past the barrel 10 before the barrel 10 has reached its maximum angle of tilt. As the slide 38 continues to move further to the rear, the angle 50 of the barrel 10 relative to its in-battery axis will continue to increase. In part, the angle 50 will further increase as the lugs 20 fully seat on the locking block 46. Additionally, the angle will increase as the supporting pivot points (locking block 46 and inner surfaces 48) move closer together.

Referring now to FIGS. 9 and 10, therein is shown the barrel 10 installed in a slide 52 that does not include an LCI. The notch 28 in the hood extension 26 is unfilled, which does not affect the interaction or operation of the barrel 10 and slide 52.

While one or more embodiments of the present invention have been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. Therefore, the foregoing is intended only to be illustrative of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not intended to limit the invention to the exact construction and operation shown and described. Accordingly, all suitable modifications and equivalents may be included and considered to fall within the scope of the invention, defined by the following claim or claims.

Claims

1. A replacement pistol barrel for reliable operation when suppressed, comprising: a barrel having a chamber, a threaded muzzle end, a trunnion portion around the chamber that engages a slide ejection port, and lugs that engage a frame locking block when the pistol cycles;wherein the trunnion portion has a top surface with a forward edge that engages an edge of the ejection port and a rear end, the forward edge lowered relative to the rear end and the edge of the ejection port such that the slide can disengage and pass over the trunnion portion at an earlier stage of cycling.

2. The barrel of claim 1, further comprising a hood portion extending rearward from the rear end and including a notch to receive a loaded chamber indicator when in an in-battery position.

3. A universal handgun barrel having a trunnion portion with a top surface having a forward edge and a rear end, the forward edge is lower relative to the rear end with at least a portion of the top surface sloping upward from the forward edge to the level of the rear end.

4. The barrel of claim 3, further comprising a chamber with a breach opening and a rearwardly extending hood adjacent a top of the breach opening, the hood including a notch to accommodate a loaded chamber indicator, if present.