construct a a shell that fits the barrel of the gun, etc. then fill half the shell with extracted, powdered and compacted model rocket fuel. then could you use a contact explosive (something very sensitive to friction and force) as a primer to ignite the rocket fuel?

my question basically is, when the hammer hits the contact explosive and produces the explosion, is this enough to ignite the rocket fuel or can rocket fuel only be ignited by a fuse/electric means.

any thoughts or alternatives would be appreciated.