Felyne Gunpowder is an incredibly useful skill at lower levels or for anybody interested in the art of Sleep Bombing. It upgrades all of your Bombs to the "+" version of their standard form. This increases the amount of damage all of your Bombs do, and with the use of the Alchemy skill, allows you to create alot of Large Barrel Bomb+!!
When used in conjunction with the 'Bomber' armor skill, you can make your standard Large Barrel Bombs into the + version and have them doing 1.5x damage. So, if you are having problems and fancy trying to remove huge chunks of life from a monster with explosives, why not try Felyne Gunpowder?!
The combination of Alchemy, Felyne Gunpowder, and Bomber is a very effective setup for use against White Fatalis when it enters permanent armor mode. This is because explosives ignore the immense increase in its defence and do much more damage than your standard attack which is crippled by it.