"Role 4.2" Mortar in US Cav "Platoon" Cold War?" Topic

I'm interested in understanding the role and capabilities of the M106, 4.2" Mortar, attached to the Cold War era, US Cavalry "platoons" in Europe.

This was a mixed unit of a platoon of tanks, a platoon of APCs (a couple of A/T APCs later), and a single M106 to presumably provide direct fire support for the unit. They contained 10 – 12 vehicles, depending upon the time periods, and TO&E structure for that – M48s initially, then M551s, and later, M60 tanks, plus M113 APCs.

From what I've read, these Cav units were tasked with finding the enemy and engaging/delaying them, screening US forces, and conducting delaying actions to buy time for larger, more powerful US forces to mobilize and engage the enemy. They were frequently at the tip of the spear, conducting patrols along the inter-German border, from the 1950s until the end of the Cold War.

I know the 4.2" mortar can fire rather quickly for short periods of time, but don't know how effective it would be as a single tube against a company, or battalion of enemy armor on the attack. It can fire HE, WP, Smoke, and perhaps other rounds.

It seems to me it would be more likely to use the WP and Smoke rounds to help obscure US forces while fighting delaying, rear-guard actions, so that they can break contact.
Of course, perhaps the HE rounds would be useful too, especially against enemy APCs/IFVs. They might even get a lucky, direct hit, and disable, damage, or destroy an enemy MBT too.

So, can anyone here shed a bit more light on the subject.

I know there are a few of you guys who served in West Germany back in the day, and imagine you can help provide more info on the subject for me, and others.

yes- good question, as I just received the kickstarter war-game World at War 85' and would like to see what the role of that unit should be deployed for.

I was an 81mm PL for a time in the 101. Basically the 4.2 like any mortar provides fire support to the other units in it's force. Including using all types of rounds i.e. HE, WP, Smoke, illum, etc.
E.g. :

Smoke would be useful when covering a withdrawal.

WP could blind some enemy units[and could start fire as well].

HE would be useful in taking out dismounted Infantry and light vehicles. Or doing some damage to heavier vehicles.

Regardless CAV units generally were not supposed to not get decisively engaged. But observe and report. They also could be use for delaying and screening. A CAV traditional mission along with recon.

One tube would not be that effective against any large unit. It would generally be best to fire all tubes at a single target or location. Varying the Sheaf based on unit size and terrain. You'd want to cover as much of the ground as you could with those tubes firing in the "appropriate" Sheaf. E.g. Regular, Parallel, etc. To block as much of the enemy LOS as possible, etc., with Smoke. link

link

I spent some time in a division cavalry squadron in the early 1980s. You may want to take a look at some of the old FMs on cavalry operations to get a handle on use of mortars during different operations. Here is one:

link

As I recall, there were times that the platoon support sections (a mortar carrier) were pulled up to Troop level to form a mortar platoon. The troop commander would not do this if the troop was spread out, say in a screening operation for example.

Good link !

In this example, combined mortars could provide more supporting firepower on a target/area whether firing Smoke or HE.

Given their security role and lack of thermal sights during the time frame, I would expect a cavalry platoon would use a lot of illumination rounds executing a screen or guard mission.

pjm

Thank you for the replies, info, and links.

So, with a quick, short-lived, 15 – 18 rounds fired per minute (presumably only for the first minute, or so), and then 3 – 5 rounds per minute, what type and size of beaten zones are we talking about?

My wild guess would be about a 100m x 100m – 200m x 200m (300m x 300m?) or so beaten zone, and perhaps a 100m x 300m – 500m linear zone, assuming the 50m kill radius I read about for these is correct. Is that too generous, or optimistic?

Thanks for those Legion 4.

I also read on-line that the "lethal radius" of the 4.2" (107mm) mortar is 50m, but perhaps that is a bit optimistic.

The mortar tracks were there to suppress opposing forces to allow the scout and tank platoons to either extricate themselves from a firefight or maneuver unimpeded. Two of the doctrinal principles of the Cavalry are don't become decisively engaged and retain freedom of maneuver.

The parent Squadron had a direct support 155mm battery to handle any serious artillery support, at least in the ACRs. The divisional Cav would usually have DS artillery on call.

Thresher01,
This video is what I've used to help determine 4.2mortar causalities.

YouTube link

Tech details: PDF link

I'm pretty sure they are spin-stabilized so they should be more accurate than other mortars.

Wolfhag

Well since I was a cavalry platoon leader in the 1970s, I have answered similar questions in the past. When I assumed command in 1976, it was just after Vietnamization had depleted M113s in units. So we had jun jeeps with M60s and ground mounted TOWs in the scout platoon. Dragons were assigned to jeeps without TOWS. I also had a Jeep as my command vehicle. We had an infantry squad with M113. As stated we had M551 section with three tracks. We had a mortar track as well. Within a year

The most tracks and men in a single combat platoon. The 1Cav Div was conducting the DRS tests for the new 1980s TOE. As such we ran different attachment combos. One I enjoyed was the merger formation. All similar tracks were in the same platoon. So we had a mortar platoon of three tracks under the XO. An infantry platoon under the junior PL. a scout/TOW platoon of six scout tracks and six TOW tracks. And the heavy platoon which had nine M551 and commanded by the CO five and aLT four. The PSG that these guys replaced went to the infantry and scout platoons. The CO track stayed with the mortars. The LT track went to the infantry. The scout pot had the Their LTs track. A very formidable defensive formation when protecting a combined open area and river crossing. Later the M551 were replaced with M1a1.

After I left the cavalry, I became the XO of a tank bin HHC unit with a mortar platoon attached. We had 4.2" mortars assigned. In both assignments the most requested fire mission was WP smoke. Next was flares at night. Smoke was key in redeployment in the defense. In the offense smoke blocked the enemy's ability to watch maneuvers and target attacking units.

Yes, the CAV mission frequently to screen, delay and not getting decisively engaged. Smoke would be the best choice. The same goes for Infantry and Armor units that end up getting similar missions.

So we had jun jeeps with M60s

When I got to a Mech Bn [M113] of the 2ID in the ROK, '85. Our Bn Sct Plt had about 7 M151s. Fortunately the next year, they got the standard at that time, 3 M113s & 3 M901s for a Mech/Armored Sct Plt.

When I was in the 101, '80-'83. For about a year, '81 or '82(?) the Bn Sct Plt had 7 Suzuki 250 Dirt Bikes in their TO&E. They could easily be loaded on a UH1 or UH60. IIRC that only lasted about a year or two ?

I'm a beg fan of WP instead, but do get your drift – smoke and really hot, hot deterrence – "Win, win".

Hmmm, hadn't read about the 3:3 mix. I've always read about 3 x M-113s (or 5 x M113s, or 5 x M-114s, before the M-150s and M-901s were available), 2 x M-901s (or M-150s with TOW before those), and 1 x M-106.

Thanks for all the detailed info.

The dirt bikes were really popular with the 19D cav scouts – right up until the time one of them tried to jump the Cowhouse Creek on Ft. Hood and center punched the cliff face on the opposite bank. Unfortunately the kid didn't make it. There had been a lot of accidents and injuries and this incident was the last straw. The III Corps Commander pulled the plug on the motorcycle deltas, and it went Army wide shortly thereafter.

When I was in 2ACR 83 86 I seem to remember the mortar plt stayed consolidated. Thersher01 is right we had 3 m113 and 2 m901 and 4 m60a3/m1. Platoon leader was in a 113 and the platoon sgt in a tank.

Hmmm, hadn't read about the 3:3 mix.

The M113s & M901s was the standard in the Mech and Armor Bn Sct Plts in the mid-80s, IIRC. The other mix as Scouts19508a mention is for the CAV.

Also consolidating the mortars seems like a good idea, that is the way we, in the Infantry, did it. After the Inf Company 81s were withdrawn from the Mech. The Inf and Tank Bns had a 4.2 Mortar Plt with 4 tubes IIRC. Massing their fires makes more sense IMO. Whether firing Smoke, HE, WP, etc.

ScoutJock … that makes sense why the bikes were withdrawn. AFAIK the ones in the 101 didn't have a major accidents. But it would not surprise me. Of course putting young Alpha-males with more Testosterone than common sense on dirt bikes … What could possibly go wrong ?!