i dont have a huntsman, but i do have the sidekick with the 5/8 breech plug w/orange primer holders and winchester 777 primers, 250 gr hornady sst low drag and i shoot 3 50gr pyrodex pellets and i've never had a problem with hangfires, the pyro pellets do have the substance on the end to facilitate ignition. give the pyrodex a try, always worked good for me