M 198 155mm Howitzer

When I first joined the Army it was as an artillery man or "red leg" as they're sometimes called.  (Red leg refers to the civil war when cannon crew wore red leggings.) And the cannon I had the "joy" to work with was the M 198 155mm Howitzer.  Just the word "Howitzer" sounds pretty awesome. It's a giant cannon in the old tradition of Napoleon.  You haul this huge cannon to the spot you want and the battery concentrates all its firepower on one spot.  It's slow, outdated and cumbersome but it can be air dropped by helicopter into places where its far more advanced self propelled brethren couldn't go.  I've never actually done this and we've always just hauled it behind a truck. 

Here we see a cannon crew loading this beast. The shells way about 100 pounds and hurt your shoulder when you have to carry them around.  Two people use a tray to hold the shell to the breach and then two people ram it in.  The second rammer takes the pole away while the #1 man shoves the powder bag hat comes in three charges, closes the breach and primes the cannon with a primmer that's like a 9mm round without the bullet.  He then takes the lanyard and gets ready to pull when the gunner or team chief say its time.  Meanwhile someone is taking the cloth powder bags out of metal canisters and preparing them for the next round.  The gunner aims the cannon according to what the Fire Direction Control tells them to aim. 
Confused yet?  It's a very complicated dance of movement, specific jobs, who goes where and who needs to stay out of the way.
Here's the breach.  On the left is the wheel to turn the cannon left or right for minor adjustments and on the right is the wheel that elevates the tube.  On either side are the aiming instruments which I think consist of magic, luck and a little old fashioned guess work. 

This beast is heavy.  When the truck pulls up to the designated location, the crew jumps out the back and immediately begin to unhook the cannon from the truck, open its legs and begin preparing it for fire. Almost always there's a major adjustment to be made so everyone has to pick up the legs and traverse the whole cannon.  Let me tell you that "bumping the trails" sucks.  Have I mentioned that this cannon is heavy?  And in 100 degree Virginian weather it sucks big time. I won't even get into the suckage of putting the camo net up and down. 
There are different types of rounds the Howitzer can use.  "Willie Pete" or White Phosphorus rounds use chemicals to burn things over a wide area. Very dangerous. Standard explosive, rocket assisted, satelite guided anti-armor and flares to name a few.  Artillery, "King of Battle."  You can't win a battle by artillery alone, but you can't win without it.
I won't even tell you the foul names my drill sergeants called artillery men.