4.2 inch illum is outstanding. Also, I am extremely fond of mortars for reducing static positions when that last bastard just won't give up.

What is the loading procedure

Assistant gunner places aimimg stakes. Gunner sets range and deflection. Loader sets charge by subtracting nitro packets from fins of round. Then the command to "Hang it" is given. Then "fire". The pin in the bottom of the tube then ignites the primer, setting off the nitro, and the rest is...BOOM!!! But all this is from memory, and I only trained in mortars for about 4 months. And only did two live fire missions, and never used one in combat. This should be pretty darn close.

The real fun part is the UNloading procedure in case of a hangfire or a dud primer. It involves sledgehammers, water and several rolls of toiletpaper.

False Muzzle is pretty much correct.

Once the gun is emplaced (aiming stakes out and so on) the crew receives the firing data from the Fire Direction Center. The Gunner applies the data to the sight and adjusts the gun to lay on the aiming stakes, the Assistant Gunner helps. The Ammo-man takes the round from from the can, removes the required incremements, removes the safety and sets the fuze. The round is passed to the A-Gunner who drops hangs it 1/2 way into the muzzle of the cannon on the command "Half Load", he then calls "Hanging". On "Fire" from the Gunner or FDC, whichever is SOP or specified in the fire command he lets the round go and drops his hand to his boot. The primer on the round impact the firing pin and the round (hopefully) goes downrange. On the M224 60mm mortar there is a trigger so if the round does not drop fire it can be trigger fired. At "End of Mission" the gun is returned to it's refered data and the bore punched.

I've only had one experience with a round that did not fire (and one with a very short WP round) and the only toilet paper I remember needing was to clean myself when it was done . Removing a misfired round is a very scary undertaking and must be done correctly or the danger climbs at the rapid rate.

Bob

Procedure for unloading 4.2 inch (aka chemical) mortar. First, wait a period of time. Then, take a sledgehammer and smack it on the base of the tube. If that doesn't set it off, you drop 3 or 4 rolls of toilet paper down the tube. Then, you fill the tube to the brim with water. The water is to ensure the round doesn't fall during the next step. Then, you get several people to carefully remove the tube from the base-plate, and verrrrry carefully tilt the entire tube forward, having the poor SOB who drew the short straw on the muzzle end to catch and quickly discard each roll of toilet paper, and finally, the round. The toilet paper rolls are there to keep the round from impacting the "catcher's" hand with the fuse end. The "catcher restrains the round by holding on to the last toilet paper roll flush with the muzzle. Then, he carefully guides both toilet paper roll and round out, and carries it to the "dud" pit. Then, you call EOD, who may choose to blow the round in place.

On the M224 60mm mortar...

First attempt to trigger fire the cannon. If the round was KNOWN to be charge 0 then this can be done by hand, otherwise use the sling (mortars recoil a lot!).

If the round does not trigger fire you may need to wait until the barrel cools, otherwise wait one minute, remove the sight and then kick the tube (attempt to dislodge the round), the Gunner needs to be holding the bipod legs.

If the round does not dislodge you will need to remove it by hand...

Wait one minute again. The A-Gunner releases the locking collar and rotates the cannon 90 degrees. The Gunner (he's the guy in charge so it's his job to do the crappy part) cups his hands around the muzzle with his thumbs almost touching in the center, the A-Gunner then lifts the bottom of the cannon. At no time can the cannon be brought back down until the round is removed. At some point in time it will slip forward into the waiting hands of the extemely calm Gunner. Place round in the dud pit and call EOD. Clean trousers.

When this happened to me it was on an Illum round during a night shoot. The A-Gunner had the tube vertical with the base pointing up and no round came out. I (as the Section Leader) had to shimmy under the muzzle of the cannon with a flashlight to look for the round. Amazingly we discovered that the round did fire but the primer had just enough oomph to move the round out. No recoil was felt and the round was found the next morning 50m or so in front of the gunline during police call. EOD was called and trousers were cleaned.

Bob

Oooooh, that does sound dicey. So the lucky guy who gets to catch the round must catch it without impacting the fuse end? I guess 60mm is too small to use a toilet paper roll to cushion the fuse end of the round, huh.

Still, mortars are cool. BTW, do 60mm mortars have an obdurator ring, or something permanently installed on the round to give them their spin.

60mm is pretty small. If you leave a gap between your thumbs and use the meaty part of your hand to catch the round just below the fuze assembly (on the ogive) you will be fine. It is scary though and needs to be taken very seriously, mistakes that get made have very bad consequences. I think the toilet paper thing might also have to do with the weight of the round and slowing it as it comes riding for the muzzle, it's easy to stop a round weighing only 4 pounds or so.

60mm mortars are smoothbore, the rounds have a obdurating ring, but all it does is seal the bore. On low powder charges you can see an Illum round fly because it's so heavy. Often it's porpoising like a badly tuned arrow. The conditions need to be just right to see an HE round so I don't remember if they do that.

Mortars are nice to have, they respond quicker than arty, if set properly they have a cover a smaller area (less dispersion of rounds), you can approach closer behind the fire, and they are organic so you usually know the guy on the gun and he knows you. Arty is great when first round accuracy is needed but it is much slower to respond.

Bob

Misfires are NO fun. Had an 81mm misfire during a night fire. Went thru the misfire drill completely, and still no detonation. Had to move the tube to the dud pit -- at night! EOD came out next day and were gonna blow the tube in place, but decided one try to dislodge the round. You guessed it -- the puppy slid right out. We practiced misfires alot, and I never liked them. sundog

Are mortar fuses hot before they are fired? After firing? Or do they have a centrifugal fuse like a 40mm grenade or an arty shell?