Hey!
Well, I worked on a Flamethrower recently.
In the end, I made 2 concepts:
Portable and stationary Flamethrowers.
Watch the video, to see how they look and work :D


You want a nice flamethrower resource pack? Here you go:
[url=www.mediafire.com/download/17yz5txietb7kfe/3D+Flamethrower.zip
]www.mediafire.com/download/17yz5txietb7kfe/3D+Flamethrower.zip
[/url](Resource Pack by Sibsib92 )


Commands (the important ones):

/scoreboard objectives add time dummy time

/replaceitem entity @a slot.hotbar.0 minecraft:snowball 1 0 {display:{Name:"Flamethrower"}­,HideFlags:127,ench:[{id:34,lvl:10}]}

/replaceitem entity @a slot.hotbar.1 minecraft:armor_stand 1 0 {display:{Name:"Stationary Flamethrower"},HideFlags:127,ench:[­{id:34,lvl:10}]}

/execute @e[​type=Snowball,score_time_min=2] ~ ~ ~ /particle flame ~ ~-0.6 ~ 0.1 0 0.1 0.05 20

/execute @e[​type=Snowball,score_time_min=3] ~ ~ ~ /particle lava ~ ~-0.2 ~ 0.1 0.1 0.1 0.5 1

/execute @e[​type=Snowball,score_time_min=2] ~ ~ ~ /entitydata @e[​r=2,type=!Snowball] {Fire:50,Attributes:[{Name:generic.maxHe­alth,Base:1}],Fuse:1,ignited:1}

/execute @p[​rym=136,ry=-136] ~ ~ ~ /entitydata @e[​type=ArmorStand,score_time_min=2,scor­e_time=3] {CustomName:"North",CustomName­Visible:false,NoGravity:1,Invulnerable:1­,NoBasePlate:1,ShowArms:0,Small:1,Invisi­ble:1,DisabledSlots:2039552,Equipment:[{­},{},{},{},{Damage:0,id:dispenser}],Rota­tion:[​180f,0f]}

/execute @e[​type=ArmorStand,name=North] ~ ~ ~ /particle flame ~ ~0.9 ~ 0 0 -4 0.08 0

/tp @e[​type=Bat,name=North] ~ ~ ~-0.1

/execute @e[​type=Bat] ~ ~ ~ /effect @e[​type=!Bat,r=1] 7 1 0 true

/execute @e[​type=ArmorStand,name=North] ~ ~ ~ /summon Bat ~ ~0.8 ~-0.5 {CustomName:"North",CustomName­Visible:false,Fire:60,Silent:1,NoAI:1,Ac­tiveEffects:[{Id:14,Ambient:1,Amplifier:­180,Duration:1000000}],Attributes:[{Name­:generic.knockbackResistance,Base:100}]}