I want to hear every instrument the midi is capable of.

Hi there.

Getting down to it, musescore appears to be quite limited when dealing with soundfont files. Each soundfont has MANY instruments that can be sythesized, but musescore will only allow me to hear the ones in the instrument list.
As an example, I wrote a song in finale years ago that used a gunshot sound. When I play this midi in musescore, it plays a gunshot. But I cannot figure out how to find that sound again in musescore even though I'm using the same soundset. I can't recreate the score because there is no option in the instrument list for a gunshot.
Maybe this is really obvious and I missed it, but does musescore have the ability to allow us to create new instruments and assign midi sound to them? Or is there a way to scroll through all the sounds in a soundset and then assign a sound to a new instrument so that we can use it when we want on a permanent basis?

I was listening to someone's composition where they used the sine synthesizer. It was a cool sound so I wanted to use it, but the sound that comes out when I select the sine synth is completely different than what they used, even though the soundfont is the same. It's very frustrating. I just want to hear all the sounds in the soundfont, not just the sounds assigned to each instrument.

Is it possible?

Thank you.