Calibrated Tech ARD g1 Recoil Reducer Performance and Specifications
7/8ths (0.875) inch diameter by 5 inches in length and weighs 5 oz.
This device is primarily intended for 12 gauge, breech loading, shotguns. However, if you can mount the device appropriately, it should work on about any long gun.Generally:
- remove the butt pad
- insert the device into the bolt hole (either end can go forward)
- Fill any space so the device cannot move along the line of the barrel
- reinstall the butt pad
The device is designed to be rigidly mounted in the bolt hole of the stock. This means the device requires the diameter of the bolt hole be at least 7/8ths of an inch and at least 5 inches deep. It does not matter which end of the device is forward. When properly mounted, the device is firmly sandwiched between the stock bolt and the butt plate.
If your bolt hole is not at least 7/8 inch in diameter (for example, most Brownings are while newer Perazzi are 5/8 inch diameter), gunsmiths may be able to modify your stock to fit and mount the device. Check with your gunsmith, but we have found the normal charge to be between $50 and $100 for this service.
You want to mount the device in such a way to transfer as much recoil energy into the longitudinal axis of the ARD as possible. This means that you want to mount the device as parallel to the barrel as possible. It is important that there be absolutely no play or movement of the device along the axis of the barrel. Any play along the axis of the barrel will make the device ineffective. If your bolt hole is more than 5 inches deep, the excess could be filled by an appropriate length wooden dowel, 5/8 inch diameter radiator hose, washers, or other such devices. But be careful that whatever you use does not compress over time, deform around the bolt, or do anything that would eventually cause a loose fit.
It is also important to not wedge or force the device into the bolt hole. Eventually, you will probably need to remove your stock. This means you will need to remove the ARD device to access and remove the stock bolt. The normal way to extract the ARD device is to insert something metal like a socket extension into the bolt hole. The magnets in the ARD will attract the socket extension. This attractive force should be enough to be able to extract the ARD. The end caps also have a center hole for a gunsmith's pick.
Recoil Reduction Performance:
Arguments about recoil have been around as long as guns have been in existence and we are not going to be able to resolve those arguments here. There are many methods to analyse this topic, but I am going to present only one. I will be writing about REAL recoil and not FELT recoil. While technical details are inevitable, I hope to keep this explanation as readable as possible.
Quoting from Wikipedia: "recoil (often called knockback, kickback or simply kick) is the backward movement of a gun when it is discharged. In technical terms, the recoil momentum acquired by the gun exactly balances the forward momentum of the projectile and exhaust gases (ejecta), according to Newton's third law, known as conservation of momentum."
Please note 2 key concepts from the last paragraph.
- Recoil is backward movement of a gun when it is fired. That is, movement into the shooter's shoulder. We will use this to define the start and end of the recoil event.
- Recoil is momentum. We will be quantifying recoil as momentum.
On a standard 8 pound, breech loading shotgun, shooting a normal 1&1/8 oz load at 1200 fps, our ARD g1 device reduces real recoil by 17%. It achieves this by converting some of the kinetic energy from firing a shell into other forms of energy (specifically, electricity and heat) that are not transferred to the shooter's shoulder. It does this smoothly and silently. There is no mechanical noise, liquid sloshing sounds, or lingering vibrations from springs.
The following images are oscilloscope traces of the output of an accelerometer mounted to our test shotgun when firing a shell. We took considerable effort to minimize the number of things that could change when running a test. For example, all tests were done with 1 single shotgun. We can only shoot a loaded shell once, so we have to change shells, but we used factory loaded shells from the same box. Otherwise, we tried to only change having an ARD g1 recoil reduction device installed in the shotgun, and not having our recoil reducer installed in the shotgun.
We tried to make the tests as standardized, reproducible, and fair as possible. A test run consists of a group of shots. All test data that we compare are taken on the same day. This is done for many reasons, including that the performance of gunpowder varies with temperature.
This also means that generally, you cannot use the data from any single test to make conclusions. A test procedure must be defined and followed, test data must be carefully collected, and statistics performed on the data to determine the characteristic behavior of the device. This also helps to prevent flukes and "cherry picking" of data. But ironically, presenting statistical data is not sexy or sometimes even very convincing. So let me show you some of the real, individual test data that we gathered.
In the following images, the yellow line represents acceleration of the shotgun. The area under the graph of acceleration is momentum. When the y values on the graph are negative, the gun is accelerating into the shooter's shoulder (ie: recoil). We are interested in the area under the graph during the period where y is less than 0.
This set of test data is for store bought, Federal Field & Target, 12 gauge, 3 dram eq., 1-1/8oz, 2-3/4 inch, 1200fps shotgun shells with #8 shot. The shells are from the same box.
These images use the same scale (2ms/div along the X axis and 0.5V/div along the Y axis).
Here is an image of a recoil event in our shotgun without a recoil reduction device.
Peak acceleration is -1619 m/s2
Here is an image of a recoil event in our shotgun with an ARD g1 recoil reduction device.
Peak acceleration is -1533 m/s2
Let's carefully compare the two graphs.
To help in the comparison of the two, here is an image of the two graphs overlaying one another, and zoomed into the area of interest. The red line is the graph of without a recoil reduction device. The yellow line is the graph with an ARD g1 recoil reduction device.
The blue area denotes the reduction of momentum, and therefore recoil, when using our ARD g1 recoil reduction device. Also note that the yellow line has a shorter distance along the X axis than the red line. This means that using our ARD g1 recoil reduction device reduced the length of the recoil event.
For this specific example, the graph shows about a 28% reduction of momentum. The data sets that I picked just happened to be a heavy recoil event for the test without the recoil reduction device and a light recoil event for the test with the ARD g1 recoil reduction device. That is just how the dice landed this time, and demonstrates the need for performing statistics on the data sets (as mentioned earlier).
On average, our ARD g1 reduces recoil by about 17%. It will work a little bit better on faster or heavier loads. It will work a little less on lighter or slower loads. As a rough approximation, a 17% reduction in recoil is like going from a 12 gauge 1&1/8 oz load to a 12 gauge 1 oz load (keeping the speed the same).
The ARD g1 was originally developed for ATA registered trap shoots, which are often 300 rounds (and more), using a 12 gauge shotgun with 1&1/8 oz loads. Singles are often shot with 1145 fps loads, while handicap games beyond the 23 yard line generally use around 1235 fps shells. Instead of carrying 2 different loads, some trap shooters just use a 1200 fps shell for everything. Shooting this many rounds with that type of load can be very exhausting. Reducing the amount of recoil the shooter has to endure helps the shooter stay sharp and on top of the game.