"USMC 60mm mortars" Topic

My understanding is – please correct me if I'm wrong – that USMC used 60mm mortars quite extensively at platoon and company level, so for game purposes would it be valid to treat them as 2-3 man teams attached to platoons as required but with the potential for them to be brigaded together as a company asset?

Organisationally, USMC rifle company had three 60 mm mortars, which were organised into a mortar section that formed part of the company weapons platoon. The other elements of the weapons platoon were machine gun section (six M60 MGs) and anti-tank section (six bazookas).

Tactically, under most circumstance it would probably be preferable to have them all operating as a single body, providing concentrated indirect fire support to the rifle platoons as needed (60 mm mortar has a pretty decent range).

Splitting them into single teams would make it more difficult to use them effectively for indirect fire. Furthermore, each mortar would need to be accompanied by several ammo bearers, as mortars tend to be quite ammo hungry weapons – you preferably need at least five men to transport the mortar and a useful ammo load in action. Detaching individual mortar teams might become relevant if the company ends up split up over various geographic locations, e.g. having rifle platoons assigned to man separate hill top firebases.

For gaming purposes, if you are playing a company sized action, it would be most sensible to have the mortars operating as a concentrated section, since they should be able to reach pretty much any point on the tabletop with their indirect fire. In a platoon level game, where the platoon is operating in the vicinity of the rest of the company, they could be represented as an off-map indirect fire asset, which might not always be available (due to the other rifle platoons also occasionally needing support).

Sone additional details for Griefbringer's earlier post.

[ From "Guidebook for Marines" -1958 edition ]

The 60mm mortar is the company commander's own light, portable artillery; and is known as his "weapon of opportunity". This is due to the fact that the 60mm mortar is always under his control and therefore always readily available for use against targets that are vulnerable to small, high explosive firing weapons.

The mortar section consists of a lieutenant as section commander, a staff sergeant as section chief, and 18 men. There are three mortar squads in the section. Each squad consists of a sergeant as squad leader, a corporal as mortar gunner, a Pfc or private as assistant mortar gunner, and three Pfcs or privates as ammunition men. The section has three 60mm mortars.

Illustration portrays following details:
Distance – mortar to O.P. = 25 yards.
Distance – mortar to target at minimum range = 100 yards.
Distance – mortar to target at maximum range = 2000 yards

Ammunition:
There are three kinds of shell used by the 60mm mortar in combat:

HE M49A2 – used against personnel and light material targets.
> It explodes instantaneously on impact.
> It weights approximately three pounds.
> It is a fragmentation shell and breaks into over 200 fragments when it explodes.
> Its maximum range is approximately 2000 yards
> The propelling charge consists of one ignition cartridge and one to four increments.

Illuminating Shell M83A2 – used to light up areas forward of our line.
> It has a fixed time fuze which goes off 15 seconds after the shell is fired.
> It weighs 3.7 pounds.
> In the body of the shell there is a candle, a parachute and a small amount of black powder. When the powder train in the time fuze ignites the black powder in the body of the shell, part of the shell near the base is broken off. The candle is lighted and thrown out. It burns for a minimum of 25 seconds with a light of 145,000 candlepower and falls at a rate of about 10 feet per second.

(WP) Smoke M302 – This shell is similar in appearance to the HE shell.
> It explodes instantaneously upon impact.
> It weights approximately four pounds.
> Its filter is composed of white phosphorus, and it has a casualty producing incendiary effect.
> The propelling charge consists of an ignition cartridge and one to four increments.
> Its range is approximately 1650 yards.

B

Blutarski, thanks for the info, especially regarding the info on the mortar squad organisation of six men. I did not have my sources at hand, so could not check what the USMC practice was (though I recall that WWII US Army 60 mm mortar squad was five men, of whom two were designated ammo bearers).

With rounds weighing 3 pounds each, and the 60 mm mortar itself 42 pounds, even a six man team team can only carry so many rounds. Especially when they also needed to bring along their personal weapons and ammo for those.

And if you want to suppress an area with mortar fire, you will need plenty of those HE shells landing in that area in short time. Having the whole mortar section grouped together allows them to easily concentrate all three tubes on the target area, and each one of them can quickly spit out a short salvo.

In gaming terms, mortar fire actions should usually represent salvoes, rather than individual rounds.

My pleasure, GB. It helps to justify keeping all these damned books I've accumulated over the years.

Re ammo-humping, I have read from time to time about ammunition for support weapons being handed out to the line infantry for carrying – extra belts of M60, extra Claymores, that sort of thing. Do you have any insights on that sort of scheme? Maybe for 60mm mortar rounds?

Just wondering.

B

Of course, direct fire with mortars is better/preferable to indirect fire in most cases.

No idea about USMC practice, but there is always the possibility of drawing riflemen from the rifle platoons and attaching them temporarily to the mortar section as ammo carriers. Of course, Vietnam being what it is, the rifle platoons might be far from being at full strenght, so there are only so many men you can draw from them. Also, expect the platoon sergeant to pick the least combat worthy men he can find to be sent as ammo carriers.

As for the M60 MG, as I mentioned previously these were also part of the USMC weapons platoon, but the MG section was likely to be used as a single unit on the field and more likely to be split up support the rifle platoons. That said, considering the rather small size of the MG squads (I think around seven men with two M60 guns), there is again only so many belts they can carry. If heavy shooting would be expected, then the supported rifle platoon might want to contribute to carrying the belts.

At least the marines still held the 60 mm mortars. US army rifle battalions had given up those years before getting involved in Vietnam, and instead assigned each rifle company three 81 mm mortars as part of the weapons platoon. These were pretty useful when the platoon had transport vehicles for them (as was intended to be case if fighting in Europe), or defending a static firebase. However, since these weapons (and their ammo) were considerably heavier than 60 mm mortars, they were far from ideal for humping around in the jungle. If they really needed to be taken into action on foot, then the weapons platoon might only be able to bring along 1-2 tubes, in order to free more men in the platoon as ammo carriers.

Ammo loads tend to be one of those issues that tend to be ignored in tabletop games, as it can involve some tedious book-keeping. However, in real world combat ammo logistics tends to be an important issue – especially when it comes to infantry support weapons in challenging terrain. In game terms, perhaps one could model small ammo piles that could be placed next to the unit to indicate the number of mortar salvoes that they still have available – this would make the book-keeping more visual.

All of this data includes WWII and was current until about 1980 when the Marines got the M224 mortar.

I don't think mortars were ever assigned direct support for one specific platoon. They are normally considered the Company Commanders artillery.

Wolfhag

Once again, I am indebted to you all – keeping them as a 3-weapon squad makes most sense to me and will certainly make things much, much easier within our games which are generally company in attack/platoon in defence (give or take).

My collection of VN reference literature includes about 150 or so personal reminiscences (remember all those paperbacks that came out in the 80s? – I bought every one I came across). One of them related a story about a fire fight in which a USMC sergeant employed a 60mm mortar in direct fire, using it as sort of a giant M79 grenade launcher and aiming by eye against enemy targets (bunkers?) positioned at ranges less than the 60mm mortar's official minimum range.

I do not recall any other details or even the book I found the story in. Too long ago.

FWIW.

B

The 60mm mortar shell had what could be considered a 20 gauge shotgun shell inside the base which is fired by the firing pin at the end of the tube and ignites the powder increments attached to the fin assembly. If you remove the four increments (powder charges) you can direct fire it to about 100 yards depending on the angle you are holding it.

Wolfhag