Ok so how about if nobody uses their own guns+scopes, etc and go for something like...
Turn up, hand over your fee to someone who issues you with a rifle and a small pot of pellets. You take aim at a selection of targets and your score goes towards a prize.
While waiting you go to another stall and get some candy-floss or have a go on the dodgems or get an elevated view of the course whilst traveling down a spiral ramp sitting on a bean bag or coconut mat.
Of course some of the barrels will be bent and sights out of adjustment but it is Fair on everyone.....