The other hand-operated ranged weapons of the time had their own drawbacks. Crossbows had superior accuracy and similar power as compared to early hand cannons. However, they were expensive to make, slow to reload and their performance was almost as severely affected by wet weather as that of hand cannons. While the handgonne could not match the accuracy nor speed of fire of the longbow, gunners did not require the special training and continuous practice from childhood required of a good bowman. Yew, the primary stave making material for the European longbow, became scarcer as the medieval period progressed. Firearms only supplanted longbows in England after almost all European yew supplies had been exhausted."
Although I'm far from a strict simulationist, we see that for the most part, D&D rules for "primitive" firearms has really got it all completely wrong. I don't pretend to be an expert on rules for guns over the years in D&D—which has largely relegated such to the fringes anyway, but which periodically get covered by a variety of sources.
Here's a few things where I think they've got it wrong.
- Although not universally true, many have damage ranges that are not comparable with other weapons, assuming somehow that firearms are more lethal than non-firearm weapons. This is absurd; but quite honestly, there's something flaky with damage ranges in general. Most weapons do too little damage (either that or most characters have way too many hit points.) But regardless, the damage range of firearms shouldn't be outside of the norm for other weapons.
- To offset this, many rules have firearms be very difficult to reload, and take a long time to do so. This is actually fairly historically accurate—but the same would be true for crossbows. For whatever reason, nobody ever does this for crossbows. This sudden turn towards a simulationist exception for firearms is strange. Either simulate or don't simulate.
- The same balancing effort is made for ranges, which for "primitive" firearms are often very, very short. This actually is not historically accurate, so its not even good simulationism.
- Misfires are popular. This might be fun to introduce a little tension and risk, but it's also fairly silly.
In general, firearms rules betray the fact that most games designers don't really care very much (or know very much) about guns. That's OK. Actually, my own rules have several of these same problems—the range is shorter than for bows, crossbows, etc.; I have increased damage, but a reload time. I might have a look at those after all.