Would not matter anyway. From what I learned, guns actually require the barrel to direct the force of the propellant forward, pushing it against the projectile, like a pressure tube. Without it, the projectile would just flop out while most of the force just vanishes as it expands out to the sides.
Not sure what temp this stuff burns at, but it seems highly unlikely it would be hot enough to set off the primer, or that the beetle could produce enough of it to sufficiently coat the rounds to have this effect.
Also, if this somehow did cause the cartridges to fire/cook off... pretty sure that would kill the beetle anyway.