by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Biofeedback scope keeps you on target
  • Vibration warns when you’re off target
  • The point
  • The challenges
  • In the mount
  • Similar system used for blind marksmen
  • Functions
  • Future enhancements
  • The name
  • Pyramyd Air
  • Summary

Biofeedback scope keeps you on target

Hunters often do not have a clear picture of their quarry through the scope. A deer will hide behind branches and a squirrel may only be partially visible. A new scope may help in situations like this.

Vibration warns when you’re off target

This new scope has been developed by Sig Sauer, as an adjunct of their very popular Electro-Optic BDX ranging scope. An engineer at Sig who also hunts knew that the software and electronics already packaged in the BDX scope could be augmented to add this helpful feature of alerting the shooter when the scope was straying off-target.

BDX scope
Sig’s excellent BDX scope automatic ranging system was the starting point for the new biofeedback scope.

How it works is the shooter puts the illuminated dot, or pip, as they refer to it, on the desired target and initializes the system with the press of a button. After that, if the scope senses a stray away from those X,Y, Z coordinates, it vibrates silently. There are three amounts of deviation that produce signals of different frequencies. The first deviation range is 1/8 to 1/4 mil and produces the fastest vibration. The second deviation range runs from 1/4 to 1/2 mil and produces a vibration of medium frequency. The final range is 1/2 to 1 mil and produces the lowest frequency of all.

The point

The point of this is to alert the hunter that he’s no longer on his initial aim point, so he can adjust. If the target moves, the system can be reset quickly with minimal inconvenience. The only control is a single smart button that is best positioned on the forearm of the stock for the index finger of the off hand to control all scope functions.

The challenges

To make this system work Sig had to modify some of the BDX hardware, but much of what was required was already in place. The software additions were small and simple to create. But the bio-feedback mechanism was the real challenge. Getting a vibrator to fit inside a scope tube proved next to impossible, and that was the big problem the engineer solved.

In the mount

He put the vibration mechanism in the scope mount, rather than inside the scope tube, itself. That allowed him a larger envelope to work with. The vibrator comes from a popular video game controller and didn’t need any physical modification. Sig told me that once they knew what they wanted to do, their biggest challenge was locating the Chinese company that made the vibrator, so they didn’t have to purchase it from the video game manufacturer.

Similar system used for blind marksmen

Back in 2009 I reported on a similar system that is used by blind marksmen. I saw it at the 2009 NRA Annual Meetings and Exhibits. Look at the fourth photo down to see what it looks like and read a little about how it works. That system is fine for target shooting, but because it signals with sound, the shooter has to wear headphones and the quarry could also be alerted. The Sig system is completely silent.


The new scope does several things for the shooter. First it vibrates when you stray from the initial target that you indicated. As you get farther off target the vibrations slow down, which produces an automatic correction response that you don’t have to think about.

Sig tested the new scope against some scopes that did not produce biofeedback and found that the same shooters were decreasing the size of their 5-shot groups by 15 to as much as 30 percent. In other words — the new scope gave them greater precision. Of course the obvious thing is the scope must be exactly on target when the system, is engaged — otherwise you’re tracking a miss!

Sig also tested this with shooters who had never before fired a weapon. Thay learned that this system reduces the time to learn how to use a scope by a factor of five! The U.S. Army is interested in the system for that reason. And, an unspecified U.S. government agency has purchased 10 of the new scopes for their snipers to use.

Future enhancements

Sig told me that with the precise satellite geolocation data that’s available to the government, the system might be able to allow the shooter to acquire a target and then move from the shooting position and reacquire the target from somewhere else, as long as the target remains stationary. This would allow seemingly impossible shots such as shooting through walls! Such scopes would probably not be available to the public, but the military and perhaps law enforcement would certainly use them!

The name

The name for this new scope remains to be selected. The Smash is currently the favorite, in honor of the optics group’s Whiskey designator.

Pyramyd Air

Pyramyd Air will stock the new scope, which they anticipate being available by the first of May. They plan an introductory promotion for the new scope to showcase their new hunting map.


Technology continues to advance at an amazing pace. Sig also hinted at a future BDX modification that involves thermal imaging and a powerful gyroscope to assist night hunters in bagging their quarry of wild hogs by actually pushing the rifle onto the target for the shooter. We will see!