[jester]

Yeah, Blackpowder would not be a good option in weapons like the M16 series due to its high carbon and corosive characteristics.

I remember accounts of the American Civil War where soldiers at Little Round Top could no longer fire their muzzle loading rifles due to them being so badly fouled with carbon from their firing. Something to think about. If a uzzle loader gets so clogged with blackpowder after probably 40 or 50 rounds what would it be like with a closed system auto or semi auto weapon?

I would guess that it could work in simple blowback and recoil weapons as most of the powder residue goes out the muzzle and there is no system to get clogged.

Bolt action and lever action weapons were originaly fired using blackpowder.

And I would venture to guess that a system as robust with large gas ports and used to firing corosive ammo like the SKS would still function for a few magazines before the carbon build up caused the weapon to jam.

Also, keep this in mind, the cartridges

30-30 Winchester was the type of cartridge loading it meant a 30 caliber bullet with 30 grains of blackpowder.

30-40 Krag, 30 caliber projectile with 40 grains of blackpowder <this caliber was modernized with a rimless casing and modern smokeless powder into the 30-06 round>

Those are some examples and the Mosin Nagants, Mausers and Enfields all were originaly designed to fire using blackpowder or cordite. So, I hope that gives you some ideas.

Oh yeah and also the old gatling guns would work a bit better as their tolerances weren't as tight as modern machineguns, more open so more carbon escaped, they fired slower, and the multiple barrels would allow you fire longer than a modern machinegun.

I would also venture to guess that many of the earlier machineguns would be able to fire using blackpowder, the Russian Maxims since Russian stuff is always crube but reliable, and the old Colt M1898 machinegun aka "the potato digger" since it was orignaly chambered for the 30-40 Krag a blackpowder round.

Of course finding such weapons and the ammo to fire them could pose a problem.