>>64179334
Cookoff was a problem which H&K and Dynamit Nobel actually solved, which is why I didn't bring it up in my post. They change the formula to increase the ignition temperature of the compound.

I really just don't see the point in caseless even for pistols, having a case is just way too practical for a firearm for all kinds of reasons, so partially or fully synthetic casings I think is a much more sensible development than fully caseless.
Say that you could make a synthetic 9mm Parabellum casing out of, perhaps, some manner of hardened starch reinforced with processed hemp fibers (I'm no materials scientist or anything, but that'd be an interesting avenue to look at IMO), and it could mimic the tensile strength of a brass casing, as well as its obturative properties, that could be a really big advancement.
Again, if this type of stuff can just be used in existing guns with little issue, that would be amazing.

Next, figure out an inexpensive but reliable replacement for the lead styphnate formulas still used in primers and priming compound. The fumes from discharged primers is probably the biggest consistent source of lead exposure from shooting firearms (more so than projectiles), that would be better for the health of soldiers and sportsmen alike. It would need to be at least as cheap and available as lead styphnate though.
Lead in projectiles can stay, that's only an appreciable issue for hunting in wetlands.