Never posted hear before but enjoyed the discussion on recoiless rifles. Was wondering if you guys could fill us in on mortars. Different sizes ect. an maybe some of the unusual ones like the Japaneese knee mortar.

woods

I am really only familiar with the M224 60mm LWCM (Lightweight Company Mortar) having been a Section Leader some time ago. I have a little experience with the M252 81mm mortar as a Fire Support Team Leader.

Generally mortars are very simple weapons designed for area suppression, marking, screening, and immediate suppression of enemy targets. Getting a mortar on target is much like any indirect fire weapon, but is done by hand rather than with a computer (at least is still is at the Bn level and lower in the Marines). Once you know where the mortar is, have it laid on an azimuth, and where the target is the Fire Direction Center determines the deflection, charge and elevation and the weapon is fired. If you want a more detailed explanation I can give it.

Bob

Bob, Thanks for the reply. They had a little peice on the History Channel about the 81mm on a show called Mail Call. I was wondering if the smaller ones were carried by the troops, what yhe round weigh and amount of explosive force they have, stuff like that.

woods

My understanding from when I was a FIST team leader is the the Marines use a 60mm mortar with a three man team... Mind you I never called fire for the jarheads, but a fellow FIST'er was a Marine. Gunny Bob can help you more with the 60 than I can.

In the Army, my experience is that the 81 mm is a vehicle served weapon only and obviously, the Four-duece is too. Four-deuce means 4.2 inch or 107mm. While the 81 uses a shell that looks like an obvious mortar round, the four-deuce's round looks more like an artillery shell. But I have only been on the gun line a few times, and only got to hang a few rounds once on an 81.

Calling fire for a mortar section or platoon is interesting...while they are pretty accurate, I have always found myself wishing I was calling arty...not mortars. As an example, to register a mortar (basically sight the base piece in) the requirement is to get one round long and one round short of the target by fifty meters. With artillery, you are only registered once you get two rounds long and two rounds short within 25 meters of the target. As a Forward Observer, we wanted to hit the target and kill it...not just scare it away. But sometime scarring it is better than nothing!

Mortars employ High Explosive rounds with Point Detonating fuse (Quick), Delay fuse, and if I remember correctly, Time fuse for airburst. They also shoot White Phosphorus, Smoke, and Illumination rounds. Maybe there are more shell/fuse combo's, but its been a while, and my memory is a bit fuzzy...

Gunny Bob, We did have a small computer that did the Fire Direction computing, but I don't recall what the system was called. Many units were still using the charts and darts, tho...

The main thing to remember about any indirect weapon tho, is that it is an area weapon, not a precision weapon. But the artillery could be called upon when precision was required... with a good gun crew, FDC, registration and converged sheaf, you could really make some steel fly!

[ 10-18-2003, 02:54: Message edited by: Trapdoor ]

The most general information can be found at www.usmc.mil . Along the left side you will see a link to "Equipment Fact File", then click on "Infantry Weapons". The 60mm and 81mm mortars are both in there.

The 60mm mortar is used at the company level (leg infantry). There are 3 in the Mortar Section of the Weapons Platoon (I am a Wpns Plt Cmdr). Each mortar has a crew of 3, add in a Section Leader and the entire section is 10 men. Setting the pieces in on a range involves first boresighting a sight to an individual cannon. Next the baseplates are laid, a direction stake placed along the direction of fire, and each mortar laid on the direction stake. Next the sigths of the following guns are aligned to that of the base piece (usually center gun). So far we have established that the sight is looking in the same place as the cannon and all 3 guns are aligned to look in the same direction also. Lastly aiming stakes are put out on the referred deflection (usually 2800 mils).

To conduct a fire mission the Section Leader takes the call for fire from an observer. He will need certain pieces of information to determine the target location in relation to the gunline. He uses a plotting board and firing tables (or a whiz wheel, an easier to use version of the firing charts) to determine what deflection (angle left or right), charge (number of increments to leave on the round) and elevation (angle of the bore in relation to the ground) in order to put the round on target. A good Sxn Ldr and observer can get a fire for effect after only 2 adjustments. 2 summers ago at Camp Pendleton I saw the new computer ballistic calculator that does all this, it's about the size of a PDA and works great. I have a lot of trouble trusting batteries though, so as long as I'm the Plt Cmdr all mortarmen in my company will know how to do this the old fashioned way.

A 60mm mortar round has an Effective Casualty Radius (ECR) of 30m deep by 15m wide. Fuses include NSB (Near Surface Burst), Super Quick, Quick, and Delay. Rounds include HE, White Phosphorous, Red Phosphorous (it's also white), and Illumination.

Our Weapons Company has a platoon of 8 81mm mortars. These are ground mounted and travel in Hummers from place to place. Much of what I said about the 60mm applies to the 81mm, except the blast radius is larger and each Section (2) has a dedicated 3-man Fire Direction Center to do the job the section leader does alone in the 60mm section. The HQ section of an LAR (Light Armored Reconnaissance) Company also has a 2-gun 81mm mortar section mounted in the the LAV-M.

I really like arty; since they have a shorter time of flight, are generally low angle (no high level winds to worry about), and have GPS units in their FDC for more accurate emplacement they can hit more consistently with fewer adjustments. Whenever we engage a target that may move we want to use arty. With a good observer, good target location and an FDC with their heads and butts wired together the first round should be a Fire For Effect with arty.

Hope this helps,
Bob

[ 10-18-2003, 05:08: Message edited by: Gunny Bob ]

No mortar experience here, but an interesting fact that I gleaned from the History channel. The Japanese "knee" mortar was so called by american GI's belief that the Japanese braced it with their knee. This was not the actually true and according to the program there were more than a couple broken legs chalked up to the improper use of these weapons before word was circulated that under no circumstance were these to be used by bracing them with your leg.

This may be a really known fact, but damn I wouldn't have known. They really do look like they were designed to be fired from your knee.

Carl

The Japanese "Knee mortar" was actually a 50mm grenade launcher. It fired a 2lb. projectile to a maximum range of 700 yards. It was mistakenly thought by G.I.'s that it was fired from the knee because of the concave baseplate.

http://www.mortarsinminiature.com/index_Jap.Type_89.htm

The Germans had a 5cm platoon mortar that I remember reading about. It was a little thing that a well trained crew could use to continously drop round's into a trash can. Can't seem to find much info on it, but I've seen pictures before. I think it's range was about 520 meters.

http://www.mortarsinminiature.com/index_Ger5cm36.htm

Our M224 60mm mortar has a range of about 3,490 meters with HE, and as the Gunny said, throws a varity of ammo. The M252 81mm mortar has a range of 5,608 with HE, and also throws a varity of ammo.

Basically the mortar fires with a fixed firing pin (some have a manually actuated firing pin) by dropping a round down the tube. There is a charge in the end of the mortar bomb that shoots it down range. Bags of propellent are affixed around the bomb to add range. You adjust the range by removing propellent bags to lessen the charge and shorten the range.

The links I've included will take you to a modeling web site, however they include the a vairety of mortars as well as technical information.

Regards,

Eric

How much can (does) the wind drift mortar rounds?

In the Korean War, the Chinese communists used with great effect a 122-mm mortar. They could fire it rapidly and accurately.

Any GI who was in Korean War combat can tell you how terrorizing they could be.

The really bad thing about mortars is that you never know they're coming in until they get there. Artillery gives you some advance warning.

Can't remember the exact statistic but mortars were one of if not the biggest killer in the Second War.

To watch a well trained mortar crew in action is pure poetry. Depending on the elevation and charge a trained crew can get 18-19 rounds in the air before the first one bursts on the ground - this does involve some slightly illegal shortcuts This has a great benefit nowadays as the computer trajectory programmes used in counter battery fire mean that it's shoot and scoot or you're not long for this world. A mortar team can get more rounds off in the time available.

In addition you're more likely to be calling on 'organic' fire support ie less likely to be told you're not a priority and it's nice to know that the bloke on the other end is going to be from your unit and knows that if he drops a round on your backside you'll be taking it up with him later on when you have drinkies in the mess.

The elevated trajectory is a great advantage in mountainous terrain, reducing the advantages of 'reverse slope' defensive positions.

Gents - I hesitate to mention it but the acronym you derive from fire support team has a different meaning over here especialy when used to denote one who provides fire support.

You know what they say; "Two cultures seperated by a common language."

Bob

Gotta tell ya, I'm proud to have been a gunner on an 81 in Nam during 67-68. Check out the web site Warriors of Hill 881south. Never heard a grunt complain about mortars. One mission, we fired close to 800 rounds, with 2 guns. FACT! Scroll through the above site and check out Magnificent and resorcful Mortar Men. Thats me on the sight, and my buddie and I on the 81. SEMPER FI

Back in '77-'81, I was an 11C1P, on 81mm mortars in the 82nd Airborne(B Co. 2/325). we retired the Division Trophy for best mortar platoon in the Division, after winning three years in a row. We used the M29 mortar, and it was a pretty good tool. We had a lot of fun with that one, and it was supposedly man-portable, if broken down into baseplate, tube and bipod, which weighed nearly 100 pounds assembled. We used jeeps and trailers at that time, we weren't gonna hump that rascal anywhere. Our platoon had three tubes, and an FDC, and we were assigned an FO team on deployments. I don't know how it works now, that was quite awhile ago, but thanks for reminding me of those days.

I'm a little late getting to this thread.

I was a gunner on the M252 81mm with 1st Bn, 1st Mar 1st, MarDiv (1/1) and 81's has a 5-6 man crew. Usually only 5 due to manpower, or lack there of. Two are ammo-men , one of those being the HMMWV driver. Then there is the A-gunner who actually drops the rounds and looks through the sight while moving the bi-pods. The gunner dials in the data on the sight then levels the bubbles on the sight by turning the cranks on the bi-pods, then braces the bi-pods while the A-gunner drops the round. Last but not least we have the Team Leader, who is usually a Sgt and he is responsible for everything his team does, or fails to do.

I was trained on the 60, but after initial training I never used it again. If I remember correctly the 60's range is 3500m and the 81's is 5770.

Good times!

During the late 80's I was a Mortar Plt. leader in a tank battalion stationed in Germany... We used 4.2" mortars mounted in M113s.
When I became a Cav Troop Commander in Gulf War Eins I had a mortar section (2 tubes of 4.2 mounted in the 113). We got into contact one day and most of the troop including the mortars had visual with the bad guys. Before the scout platoon leader in contact could finish his call for fire the section chief had direct laid his tubes and had rounds in the air!!!!
Someone asked about wind drift...as mentioned, that is factored into the elevation and deflection solutions based on several inputs...MET data is included in those solutions through a very simple and fast process...which as I understand it is all automated now in Palm Pilots! But even back in the days of #2 pencils it was pretty fast...
The MET data is fed down to units on a regular basis and is compiled by larger artillery units with staff specially trained in this process. Its typically passed through the Battalion Fire Support Officer (usually a cannon cocker) to the mortar sections/plt...

[ 11-19-2003, 07:07: Message edited by: Kentucky Nimrod ]

Hey, nimrod, who were you with in Germany? I was in 3d ID during that time, 3-4 CAV, so I wonder if we ever met.

Wish my Dad was still here to talk to you guys. His initial War2 deployment was as 60mm Mortar Instructor teaching Chinese troops at Ramgarh, India in 1942-3. From there he went into combat in China, India and Burma. He had some experience with mortar duels with the Japanese. Jungle warfare engagements in the Hukawng and Mogaung valley campaigns and Myi-kyina that blasted the enemy out of his jungle positions and left thousands of dead.

120,
Was in 3-63 Armor, Kitzingen...Harvey Barracks. 2d, BDE, 3ID... "I wouldn't give a bean, to be a fancy pants Marine..." (badly out of tune...dogs howling....children screaming in the background ) IIRC 3-7 Cav was 3ID's Div Cav Sqdn..in Schweinfurt. My company was OPCON to 3-7 for go to war. LTC Eric Shinseki was the Cav Sqdn CO when I was there...
Nice to meet another Marne Man online...Since this is a shooting forum I would also like to add that I was High Tank on the Tank Qualification (Tank Table 8) course in Grafenwher Germany in 1985 for the entire 3ID (roughly 200 tanks) And during 1986 I was high tank in my Brigade on the same course... Over that same period of time my crew had 100% turnover.. I LOVE shooting tanks...

Hey, Nimrod. Talk about your small worlds. I arrived at 4-4 CAV immediately after they transitioned from H Series CAV to J, and from 3-7 CAV to 4-4 CAV. I was also in Ledward/Conn Barracks when we reflagged to 3-4 CAV.

Small world.

"So feed me ammunition, keep me in the Third Division, This dogface soldier boy's okay!"

You had to be there.

Now hear this:

www.metalstorm.com

According to the Marine morter-men I knew the difference between the Army guys and the Marines was the Army guys had to use the tubes for accurate fire and the Marines just threw the morter rounds like footballs. Seems in the Corps they never taught the guys they were supposed to use the tube for anything other then pointing out the direction of fire.
Jim