Good point to reinforce the weapon if you are going to burn hho.This youtuber has an experiment on this.Can't find the papers for the moment, but from memory, laminar flame front speeds of propane in air at 1 bar ~ 0.4m/s, hydrogen in air ~100m/s, they're both much faster (between 4 and 10 times faster) in stoichiometric mixes with O2 and at pressure.
I already uploaded this video somewhere here, I leave the link: