Yep, scares the living daylights out of me when riding through a forest along a valley. The trouble in a forest, you cannot see where the shooter is and which direction he might be shooting.

I worked in an apple orchard with the gas guns used as bird scarers, and they aren't particularly alarming (although we had visitors and new workers dive for cover occasionally).

And, I've had shooters on the property fire big rifles almost next door where I was staying. That got my attention.

But if I hear them in open country, I usually ride as quickly as I can out the place. And I know that ducking on hearing the shot isn't much good because if I get hit... I won't have heard the shot.