You can certainly make your own black powder, smokeless might take some doing. A set of dies made on a lathe can turn out primer cups and anvils, you can make priming compounds out of several things. you can turn brass cases on a lathe (certainly not cost effective now, but if you had no other way)Ammo can be made from scratch.
If it comes to a full scale revolution, homemade pressurized flamethrowers, all sorts of weapons can be made.
You can certainly make your own black powder, smokeless might take some doing
During WWi Germans make an ersatz (subsitute) powder from
ammonium nitrate and charcoal ........