Enchanting a double musket?

[Grimmzorch]

Dies a double musket count as 2 weapons for enchantment purposes or one?

[avr]

Strictly by RAW a double-barrelled musket is one weapon only and not a double weapon. Given the way spellslingers can only enhance one barrel of a firearm at a time with their class ability though there's room for a house rule otherwise.