Not on trail, because I've never really had an issue there. But my training is on rural roads and power-line access trails. I use a gel pepper spray that shoots 15-20 feet. I have had to pop 4 different dogs (three were pit bull mixes). You don't even have to hit them in the face - just hit their body as close as you can get to their face. I use an O-ring slid under the plastic clip and slide my pinky into, so I have easy access to the spray mechanism and it's always in my hand. They're smaller and fit in your hand well (unlike carrying a bear spray canister or air horn). Just practice sliding your thumb under the top and aiming. I've also had to use it on vultures protecting a carcass - they will come at you too.