[SuedodeuS]

To make the math easy, let's assume your army can get powder for $7000/lb. This means each grain costs $1. Thus, each round for a Theskan Heavy Caliver costs $50.857. Now, with powder as costly as it is, you want every shot to count. So, while you'll be firing in formation, you also want all of your soldiers to be good shots. After all, DnD follows a similar paradigm to the Greek epics - and when individual combatants are as game-changing as they are in, say, the Illiad, you want your soldiers to be able to hit Achilles rather than just sending some rounds in the general direction of the Myrmidons.

Even so, we'll assume 10 shots is sufficient for proficiency. This means you're burning through about $510 to train each soldier, and you aren't allowing them to practice outside of this. Your soldiers go through basic, learn to march, shoot their weapon a few times, and then it's off to war. If we assume the reusability of the devices (those $510 you spent training Joe Guy are gone as soon as an orc hits him with an arrow) can allow them to be about twice as expensive as the powder, and we assume that you only need about one-quarter as many such weapons as you have soldiers (as they aren't all going to be training at the same time), we're looking at an upward limit of around $4000 per training musket. Would it be possible to build such a device (with illusory sound, bullet, and recoil) for so cheap? Keep in mind that the soldiers of a military with such equipment are likely to be much better shots (and probably quicker to reload) than those of militaries that lack such devices.