NRA Museums regularly publish on their social media pages a series of firearm images under a title “GUN OF THE DAY”. Recently, they shared images of a weird looking experimental shotgun with a complicated mechanism designed to counter the recoil. By doing a brief research, I found the patent of this gun which will allow us to examine and understand its mechanism better.

Here is the description text from NRA Museums Facebook page:

GUN OF THE DAY – Recoil Counter-Vectoring Patent Gun
While once an unusual feature of our Steampunk Guns exhibition, this patent model represents an attempt to create a gun with dramatic recoil reduction. Pulleys, springs, and reciprocating counterweight fixtures give this test platform extremely light recoil when fired and it didn’t go unnoticed. American designers from General Dynmatics and Kriss USA, as well as Chinese companies, were among the international parties filing paperwork related to similar patents.
Bore: 12 ga.
Production Date: 1990s

The patent (US patent # 5585590) was granted to a gentleman named Frederic D. Ducolon in 1996. It describes a mechanism with a recoiling barrel assembly (barrel and bolt carrier group) and a counterweight assembly attached to the rearward recoiling parts via a system of cables and pulleys. Upon firing, the barrel assembly recoils rearward and forces (via the pulleys and cables) the counterweight to move forward twice the distance of the recoiling parts movement. The whole mechanism then returns back driven by the return springs. The inventor also notes that preferably the counterweight assembly will also have a throw-weight mechanism that will be shifted forward and downward at an angled declining path (58 on the drawing below).

Here is also the summary of the invention quoted from the patent.

The present invention provides a recoil counter-vectoring gun with a gun barrel assembly and counterweight assembly independently slidably mounted on a frame. The gun barrel assembly includes a barrel and a receiver having a bolt therein and will longitudinally reciprocate on the frame between a forward position and a rearward position. A means is provided for firing the gun when the gun barrel assembly is substantially at its forwardmost position. An adjustable recoil counter-vectoring mechanism is provided which comprises a counterweight assembly which longitudinally reciprocates on the frame between a forward position and a rearward position independent of the gun barrel assembly, a fixed pulley mounted on the frame, a traveling pulley mounted on the gun barrel assembly, and a cable means. The cable means has a first end fixed relative to the frame. It then passes over the traveling pulley, the fixed pulley, and toward a second end which is attached to the counterweight assembly. When the gun is fired, the gun barrel assembly recoils rearwardly such that rearward movement of the traveling pulley causes the cable means to pull the counterweight assembly forward on the frame a distance substantially equal to twice the recoil distance of the gun barrel assembly.

Another aspect of the present invention includes providing at least one throwweight assembly mounted on the counterweight assembly for movement between a forward and rearward position. The throwweight is shifted forwardly on the counterweight assembly at a predetermined position relative to full forward movement of the counterweight assembly. In preferred form, the movement of the throwweight is at a downward angle relative to sliding movement of the counterweight assembly and may be guided along a flexible cable having opposite ends supported by the counterweight assembly.

Do you think if further refined this idea could become a reasonably simple and working firearm? Share your thoughts in the comments section.

Images from www.nramuseum.com, US Patent # 5,585,590