The idea that someone who is vision impaired or totally blind shooting may seem strange at first, with a few modifications it is very possible. In fact whilst I only have light perception in one eye, I am still one of the top international VI shooters and I compete against sighted shooters in local competitions in the UK.
The basics
A VI shooter is able to shoot in the same position as a sighted shooter and most of the equipment a VI shooter uses is the same equipment as would be used by any other shooter. The main differences is the use of an audio aiming device and the help of an assistant.
The audio aiming device is an electronic device which replaces the standard sights on the gun. The new systems approved for international competition detect an infrared LED which is placed 6cm below the centre of the target. As the shooter approaches the target, the aiming device, via earphones, produces a tone which gets higher in pitch as the distance between the point of aim and the centre of the target decreases. Thus the shooter can identify the centre of the target by listening for the highest pitch tone.
There are a few things which the audio aiming device cannot do and this is where the assistant comes in. The aiming device must be able to see the infrared LED before it can give a tone, so when the shooter is approaching the target the assistant may give signals to indicate the direction the shooter must move to find the target. Also should the shooter find a target other than their own, then the assistant may indicate this to the shooter. Once the shooter has found their own target and the aiming device is giving the shooter a tone, the assistant should let the shooter complete the shot independently.
Additionally the assistant may help the shooter find their position at the start and also may give the shooter information about where shots are hitting the target.
In competition communication between the shooter and assistant should be done non-verbally, eg. through touch signals. However in training, particularly with beginners, it may be simpler for the shooter and assistant to communicate through speech.
What types of shooting are available?
The answer to this question possibly depends upon the goals of the shooter. At international level standing air rifle and prone air rifle competitions are available. However at national level there may be additional competitions available, such as a supported standing air rifle discipline where the rifle is rested on a support stand whilst shooting. I have even fitted an audio aiming device to an air pistol, however due to a combination of the additional weight and being able to correctly align with the stand I could only recommend doing air pistol from a support rest.
I will only discuss the use of the audio aiming device on air guns used at 10m, mainly because this is what the devices were designed for. Anyone who wants to experiment may have success using them for other types of shooting, but be aware you are doing things the equipment was not designed for and so you should approach it with caution.