How a mortar works?
 

Just out of interest, does anyone here know how a mortar works? Is the round self contained, or do you have to have some kind of power charge (I'm talking 60mm, 81mm that type of thing)? If so, is it possible to use smaller charges for shorter distances, or do you just use real high trajectories for that?
Thanks in advance

Self contained, but there's more to it.

The internal charge is usually insufficient to provide enough power to propel the bomb any real distance. This is usually for all size mortars. Charges, which are often just semi-circle, plastic, ring shaped charges filled with propellant are added (or removed). An 81mm might have up to four. They are connected around the skinny part of the bomb near the bottom by the fins.

So in some situations not only do you need to figure out bearing and elevation, but also what charge setting to use.

I think most mortars can have their self contained propellant range increased via increment charges.

ok, thanks for that info. Do you know if these charges take much time to attach?

I've found this on wiki, but it took me a while to find because I didn't know what I was looking for:
The charges on the 80mm rounds govern how far that particular round with travel. Each round that the M252 mortar fires has four semi-circle shaped charges that can be easily attached, or stripped by hand. While the rounds can fire without the aid of additional charges, to reach farther targets more charges must be applied.

Calling Paul Mulcahy! Or perhaps Gunner Law!
 

Paul, Law?

Any insight, albeit your skill sets aren't specific to High Angle Hell?

No time. By the time the No.1 has laid the bearing and elevation, the No.3 will have the ammo ready (this includes setting the right charges as the Mortar Fire Controller indicated).

The charges come pre-connected, but taking them off or putting them back on, only requires a flick of a finger so yeah, no time. They are only loosely wrapped around - not tight or anything.

Actually my first MOS was 11C (mortar gunner), but what the other minds on this board have said are right. I can add that the 4.2" mortar uses "cheese charges" -- these are about the size a color of a slice of cheese you might put on your bread, but made of nitroglycerin and beeswax. They have a hole in the middle to wrap around the tail of the charge. 4.2" mortar rounds don't have fins (the barrel is rifled), so there is a simple retaining ring to keep the charges in place. The rounds come with enough charges to propel the round to its maximum range, so the one of the ammo bearers (there are two on a 4.2" crew) "cuts charges" -- he tears off or detaches (they come in 5-"slice" increments as well as some single slices and one 10-pack) the parts of the charge not needed. A good charge cutter will be 2-3 rounds ahead of the round being fired. If you need to drop close, you can fire the mortar on charge 0 -- no propelling charges.

Then comes the best part of 4.2" mortar gunnery -- destroying the unused charges when you're done. You dig a bit pit, throw the charges in, then throw a burning book of matches or a stick on fire into it and run. Big fireworks display, and it sounds like a jet engine for a few seconds.

Older 81mm rounds have bagged charges -- 7 for an 81mm. The 60mm are similar, but only have three charges. You just unhook what's necessary.

Only thing I can add is some pedantry-- a mortar shoots "bombs," not "shells," according to many sources.

I am qualifed on the 60mm mortar and have always wonder how far the basic round no extra charges would travel

I was wondering something.

Should Mortars always be used in pairs, or is a single mortar just as effective in a pinch? Anti-Armor weapons like the SMAWS, Carl Gustav or PzF-3 seem to be good when used as single weapon team (Gunner, Asst. Gunner & Ammo bearer), but I was wondering about Mortars. Can a group that has a single mortar team work just as effectively? Or a single gunner with two assistants be able to operate two mortars?

We operated guns with 2 man mortar crews. Gunner and A-Gunner with them prepping ammo before hand and the lone ammo man in the section and the corpsman and radioman and section leader lending a hand.

Mortars (and artillery) are not necessarily best employed by firing the entire gun line, be it 2 guns or 20. It depends on the type of mission they're performing.

That said, you'll most likely not get the most bang for your buck when you go to FFE (Fire for Effect) if you're only using one tube.

((While I'm not an 11C, I am an Infantry Company Commander, graduate of the Infantry Mortar Leader's Course and own the Battalion's Mortar Platoon.))

That sort of depends on where you're from -- Americans and South Koreans call them shells, for example, while Brits and Germans call them bombs.

Not every army is the same of course, but I can say...

Part of keeping them in groups (of say 4 tubes) is due to the area effect of the bombardment (like Eddie said) with having a suitable FFE factor. However, another part is due to the limited number of personnel in your mortar platoon and the limitations of the crew...

Beyond 60mm, larger mortars are usually behind the FEBA so that they are indirect only. That means you need a MFC (mortar fire controller) to coordinate with fire controllers (spotters), and work out the calculations. There are only so many of these guys, so splitting up all you mortars up means you would have some tubes sitting idle (as in there isn't one MFC per tube). So one MFC can only do so much at a time.

So if a battalion has an eight 81mm mortar platoon, they are likely split into two 4-tube groups. Each group would have a one MFC team.

A single mortar is usually not able to preform indirect fire missions independently of a MFC. They have enough to do as it is without worrying about communicating with spotters and plotting. The MFC also will limit the number of rounds per fire mission, so you don't have gunners blowing off more than they should (or not enough).

I know I am not explaining this very well, its been a looong day here at work. But to summarize - they are grouped for the effects of firepower and due to how many MFCs you have.

For the question of 3 guys dividing their time on two mortars? If they are mortar trained, then yeah, but their effectiveness would be obviously reduced. It would probably be best to just add a 4th guy and split 2 men each (instead of 3).

Well...this is more geared towards the older mortars I'm familiar with, but the book minimum ranges for M-19 60mm mortar using the small M-2 baseplate is 40 meters. For the M-29 81mm mortar, the book minimum range 100 meters. For the M-30 4.2" mortar, it's 770 meters.

That said, if your gunner know a few tricks, like propping up the legs of an 81mm mortar or hand-holding a 60mm mortar without the bipod, you can literally drop the round right on top of your self, or very close to yourself. Those minimum ranges are for safety. A 4.2" mortar, on the other hand, has a definite elevation maximum; on charge 0 at max elevation (which is NOT recommended) you can expect that heavy round to travel no more than about 50 meters. For the 81mm on max elevation on charge 0, you can just about quarter the minimum range above (and the old M-29 can superelevate; don't know about the newer ones). For the 60mm, if you are using it handheld, you can almost use it as a grenade launcher; some countries make a HEAT round for their 60mm because of that. If you are using the bipod, you can expect about 20 meters on charge 0.

60mm mortars are the most difficult to quantify, since they can be used as indirect fire weapons and to an extent direct fire weapons, when they are handheld.

They are also mounted as a direct-fire weapons on some AFVs, such as the French AML-60 armored car. The 81mm mortar was also pintle-mounted on US Navy riverine craft such as the Swift Boat for direct fire.

Here is a pic (stolen from the Post-apoc picture thread here on the forums), showing the charges on the bottom of a mortar:

http://forum.juhlin.com/attachment.p...8&d=1248909257

ahh, nice. thanks very much

Okay, I have qualed with the 60mm and 81mm and spent a few years on a 60mm gunteam.

81s

They have the following components;

Guntube
Bipod
Baseplate the round type
Sight


Other equipment;
Aimming stakes <the red and white candy cane metal stake that comes in three sections and slides together>
Aimming stake lights, three of them, 2 red I think the third is orange, this clip to the aimming stake so you can sight in and aim at night.

Bore sight; this slips over the muzzle and you can level the gun using the bubbles and fire this way.

Further, a compass placed on the dozetail slot of the bipod can be used instead of a gunsight to sight in a gun.

Sectional cleaning pole with worm <corkscrew looking thing>

Plotting board, a square board with grids, a rotating arm in the center of the board. So it looks like a large piece of graph paper with a protractor arm that roates 360 so you can plot your rounds.

A data book as well as the knowledge of the gun crew who know what charges and elevation and deflection to use, and of course calculations are done by the FDC, the FDC at Bn level for 81mms and above has a larger dedicated FDC crew.

And the mortarmen also can be issued a funky vest that looks like a grenadiers vest that has pockets to hold mortar rounds on the front, it held I think about half a dozen rounds. I only saw them twice once in Infantry School and once in the armory on a working party. And in some movie about Korea where some Americans and Greeks are lost behind enemy lines, they encounter some British Troops in a Sherman Tank and they see an American mortar team of two running across a field and one of them had a vest as I am describing.

And of course binoculars are also available.

And the only spare part issues to mortarcrew, a FIRING PIN <for the 81mm>


At the 60mm level,

Same equipment as above,

They will also have a small rectangular baseplate
They do not have the spare firing pin!

The following is the EXACT SAME as the 81mm;

Aimming Sight
Aimming Stakes and Lamps
Round Baseplate
Plotting Board

The 60mm can be trigger fired, and it can be fired via a trigger, or the firing pin can be locked and it can be drop fired, the 81mm can only be drop fired.


A Fire Direction Center, at this level I have seen consist of the section leader who was also helping on a gun with the platoons Corpsman running the radio. These were called fire missions so the Corpsman who we brought up to speed took the info, plotted the info, the Section Leader would check and verify, issue the order, the guns would be dialed, the teams would prep the ammo and then the guns would be "up" and ready to fire.

In our section we had 3 60mms, seldom did we have more than 2 guns ready with just three man crews with the section leader and the Corpsman running the radio and FDC.

In our unit, most mortarmen were well skilled as FO's since they had to know the assorted calls for fire to be able to plot in the FDC. Simply put, when the guys calling for fire called whatever the fire mission, you had to know and put that data into firing data for the guns. And this also required excellent map and compass and distance determination skills.

Also, the whole aiming and leveling of mortars is similiar to other artillery the sight was the same! Thus, in theory, myself as a mortarman, I would be able to dial in the data on a 60mm mortar and the same method dail in the data on a 155 or 105, the problem of course is familiarization with the weapons system, the assorted adjustment knobs to bring the muzzle around.

I personaly find the rules very lacking for mortars in the game. As I recall we had three main drills;

Setting the gun up from each man carrying a seperate component. This was sometimes a exercise in commical acrobatics! We would move like sliding into place but slamming our component where it needed to go, as well as doing tumbles and rolls and leaps to get in place and out of the way. And when the Gunner called, "OFF MY GUN!" It was all on him to dial it in.

We had it down to under 20 seconds!

And then we had large deflection and small deflection changes.

Large we had a time limit of about 30 seconds, we had it do to under 20!

Small deflection changes we had i think 19, we had it down to under 10!

And then use, 60mms can fire direct fire!

You can boresight them, and we could even fire them without sights! Just use a rough guestimate of distance and direction, the 60mm had a cool range band level thingy on the gun so it determine the distance by the degree you lowered or raised the muzzle.

And also, you can put more than the max charge on a mortar. It is done OFTEN! I think the max charge was charge 5, the max we did was charge 8! It increased the range by about 40 or 50%.

Here is another thing to consider.

We had used rounds from the late 40s these were old and had less range, I had my "lil green book" stolen with all the nomenclature so I can't tell you, it had the types, years they were used, colors, ranges, weights, danger range and all that other good stuff.

But the Korean War and WWII stuff was old with less range, the Vietnam stuff into the 80s was the normal stuff we used, then we got some new stuff! AWESOME!!!!!!

And with stocks in Europe, I think we would have especialy with the many build ups that we had durring Korea, durring the assorted times of buildups in the 50s, 60s and 70s I would imagine LOTS of ammunition from those times would be the most common rather than top of the line modern ammo, at the very least, it would be equal, with shipping shiploads of ammo over, but then alot of that ammo would have been taken from assorted ammo dumps in the US that had been stockpiled over decades as well.

Thanks for the info, but now I have another question: the tw2 book describes the wojo combo mortar as having wooden sabots to use 60mm mortar bombs - would these sabots shoot out of the barrel when fired and be lost down range or at least damaged?

Almost certainly. The sabot is designed to wrap around the round and are fired out of the barrel. After firing, they fall away from the round and, if they weren't damaged in the intial firing, chances are they'll be in less than perfect condition after hitting the ground.

I would also add that the sabots would for the mortar reduce its range and accuracy.

And yes, they would be burnt and cracked in the initial firing, and as was stated them falling from so far, or hitting the ground at any speed they would be cracked, chipped, dented and in pretty sad shape.

I reckon a viable alternative to wood for the sabots would be something along the lines of paper mache. Much easier and quicker to produce and much lighter (always a good feature in a sabot). Expanding foam or carved styrofoam would be even better but not necessarilly as easy to find the raw materials.

You also have to think about the residue it would leave on the inside of the tube and all of the cleaning that would be necessary to get it off. Probably not the best thing for the mortar tube itself.

True but wooden sabots would have their own problems. Pine would be easy to work with but contains alot of resin so it would present cleaning issues too. And many lighter woods expand greatly and/or warp when exposed to moisture so they would have to be carved smaller than the bore diameter to avoid nasty firing accidents. Harder woods would be less prone to warping and would probably be reusable as sabots but would be harder to source and machine. I guess you would lathe a length of wood to the required diamter, bore a hole down the middle, saw it into disks then cut each disk in half.

Don't misunderstand. I'm not a proponent of either. I'd rather fire 81mm rounds from it.

That said, the problems from wood would be a lot more easily mitigated with more options than paper mache or styrofoam, because no matter what type of paper you use, it's still mache. The same with styrofoam.

The styrafoam would melt, and cover the barrel with melted goey plastic that would harden and made the gun unusable, or worse, cause a hangfire <BAD MOJO!> styrafoam also can burn, imagine fire touching those charge bags? Another case for BAD MOJO!

Paper Mache, it would be blown to pieces, or burn up and you would not get the tightness in the bore, which would cause the round to wobble as it left the bore which would result in a "IRRADIC ROUND!" this is another case for BAD MOJO! When you have such casses the whole crew shouts, screams, waves their arms and does a monty python reinactement of "RUN AWAY! RUN AWAY!" because that round is going someone other than where you intended it to go, and it is going to go much shorter too.

Granted, an 81mm round down the pipe of an 82mm no biggie but when its a 60mm down an 82, and its sabot was bad well that as I put it in my Spanish class, "muy malo....muy muy malo."

Okay, so foam and paper mache would be bad. Surely there would be a better way than a wooden sabot. A slide-in metal tube insert of the correct bore diameter?

As a complete armchair military man... 0 actual service..

Can anyone tell me how a single person could man an 81mm - would it just take 3x as long? Rules have fire rate of 1 per round.

Also, the smaller 60mm, would that be easier and therefore not x3 or ?

It's just I have a player in my campaign that loves to get a mortar set up and fire it solo and I dont know how difficult this would be.

As long as the ammo is already prepped for the required fire mission and plotted I would say x2 as a GM. He could load/fire on his own and periodically check for/make minor adjustments to the leveling bubbles (as they get knocked off with repeated shots).

The 60 should be the same, unless fired direct. Then it can just be using the tube (no bipod), and can be (and is) handled by one man. Especially so if he sets it to lever action and not drop fire.