It is a normal physiological phenomenon for human beings to blink their eyes. The average rate of blinking eyes for people is to blink once in about every six seconds, more or less. And when people are under a condition of nervous or anxious or so, they will blink more than usual. And when they calm down and recover to the normal mood, their blinking frequency will accordingly return to the normal level. Therefore, you had better let yourself calm down and relax when you are shooting. Take a deep breath and then focus on the target. You can appropriately extend the interval of blinking so that you can have a little bit more time to make sure that you can shoot at the targets.
Well, in daily life, blinking problem has just annoyed many people. And that can be kind of serious. For your situation, I have to say that it may be related with the nerve system of your eyes, when you are shooting. As we know that when you are shooting, you may feel kind of nervous. And because of that, of course, it will just affect your eyes, leading to frequent blinking. So to treat it, you need to have a deep breath first. And then just calm down. And in that way, maybe it can be helpful. Also, having some ice on your eyes can be effective too. By the way, you should know that blinking can be also caused by eye infection too.