If gunpowder didn’t react in the way it does, what would we be using in bullets and the like? I know there’s plenty of other explosives for generally blowing things up but what else would work in firearms (both older blunderbuss/musket types and evolving into modern bullets)?
We actually don’t use gunpowder for firearms anymore. The old style gunpowder is now renamed “black powder”, and only replicas and antiques use it.
Do you mean modern gunpowder (nitrocellulose) or old black powder? Because if one didn’t work, the other would have been useful. If you exclude both, then I assume an ammonium nitrate propellant, or another potassium nitrate blend if that’s allowed, would have been acceptable. If you’re going to exclude all nitrate chemistry, then firearms would have had to wait for perchlorate chemistry, which can also produce deflagrating “explosives.”
Interesting. I’ll admit that I was unaware that we no longer used “real” gunpowder. I suppose I was just curious where the next technological leap in weapons would have been if good old fashioned gunpowder didn’t exist but I’m guessing then from the answers it would have been some other compound in the same family. I don’t know the chemistry enough to set good standards for what should count or not.
Some mixture of sugar and potassium chlorate would probably suffice for blunderbuss as well.
Or Sodium Chlorate. Me and my best mate made a lot of things go very boom in my mis-spent youth using that stuff - could have killed or badly injured ourselves on a couple of occasions, but for dumb luck.
Speak to me, brother! Why are so many of us still alive?
Jeweler’s rouge.
[I wonder how many people will get the reference :D]
Not 'round here, they won’t.
Most of the dead ones don’t post here.
I have a Shadow of a doubt that won’t work.
Check the recent rule change about zombie threads. 
Compressed air?
Granted not as powerful but than again if we had no explosive powder to use for guns we would not know the difference anyways.
Air-rifles were developed in the 18th century and were surprisingly effective- Lewis & Clarke had one.
Personally, I suspect the next quasi-logical choice (for the era) for a firearm propellant would be petrol. I doubt it would work especially well in small-arms, but you could manufacture a mortar or smallish cannon with that as the propellant, I’d say.
Because some of us smarter ones let the other guys do it while we watched.
And if we’re talking something larger than small arms, say, on a wheeled gun carriage, steam becomes an option, if no internal combustion chemicals worked.
And it almost got Sherlock Holmes!
In my misspent youth, I obtained a book called “Improvised Munitions” – an old army manual. KClO3 and a few other ingredients made for a fine plastic explosive filler.
I made myself a little “device” and put in in a hollow of a rather large tree next to our aluminum lawn equipment shed. “Little Boy” made a nice boom that shook the tree a surprising amount from top to bottom as I jumped in glee like Adam does when cement trucks disappear.
The tree, all of the sudden, started to lean like the tower at Pisa. More and more, until finally with a loud crack, it fell on the shed, crushing it and all of the equipment inside.
I was grounded for almost a year and a half while I substituted for the lawn equipment with my bare hands.
I have since learned the error of my ways and have discontinued the search for small amounts of antimatter.
I can trump that.