Spouts were generally used to load cap n' ball revolvers, not long guns. A spark in the barrel when you throw a charge down bore from a flask into a long gun will turn the flask into a gernade and you'll be holding it, not a good deal in anyones book. As to use, you put your first finger over the spout and turn the flask so that powder will run into it, use your thumb to work the lever, let the lever go then turn the flask back over and remove your finger from the spout and you've got a charge of powder to put into the cylinder of your cap n' ball revolver. You can also just put the spout down into a powder measure and thumb the lever until your measure is full. Then use the measure to load your long gun, that way if it does go up you're only burning one charge of powder not the entire flask. Hope this has been some help. In Frith.