I think we need to look at these mortar rounds carefully, collective googling effort needed:

[originalpckelly]

These things look like a number of American designs:
M374A3 HE

TM 9-1015-200-10: M374A3
HE cartridge is constructed from pearlitic malleable cast iron and contains about 2.10 pounds (0.95 kg) of composition B explosive. It uses the M205 propelling charge, consisting of four horseshoe-shaped increments fitted around the tail. The cartridge is painted olive drab with yellow markings. It can be fitted with either the M567, M524, or M532-series fuzes.

[durtee librul]

1. Can you say..

guns and ammo for hostages?

[originalpckelly]

2. Here are some more with the general shape:

All of these are American designs. If they did come from Iran, they may be imitations of our mortars.

[laststeamtrain]

3. See this:

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=103x262632#262645

[SoCalDem]

5. and these

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=389&topic_id=188128&mesg_id=188128

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=389&topic_id=188128&mesg_id=188153

[yardwork]

4. How many U.S. munitions depots have been taken over by Iraqis?

How much ammunition has been stolen from the U.S. forces?

We've known for years that the Iraqi insurgents are using our own weapons against us.