the strength/ferocity of the chop is not nearly as important as the timing of the chop.
most players rush their shoulder rotation to the point where they can't chop correctly. the shoulders must pause (or at least slow down) in order to trigger the chop.
also, there's a lot of misconceptions about what the chop really is, because the term chop usually gives people a vision of some kind of quick strike. the chop is more like a wrist shot in hockey, with your arm being the stick blade and the disc/hand being the puck. your peak in speed should happen at the moment the disc wants to leave. it's easier to perform with a slow build to shift the disc's momentum and a hard "shove" at the end.
The right peck drill requires 'igniting' all muscles and push the underarm out to deliver the disc at the hit.
this isn't really true. it's more of a drill that puts you into the correct positions and is supposed to help you build your timing for how to hit a disc. usually this involves SLOWING DOWN your upper body during the early parts of the throw in order to learn to accelerate at the later part of the throw.