Light Mortars

[JonS]

US has 60mm mtrs at a low level, as does Canada and NZ.

[flamingknives]

The US Army has a 40mm automatic grenade launcher, which is definately a vehicle/support weapon, and the 40mm M203 underbarrel grenade launcher.

I recall reading (in fact, on the British Army website) that the aquisition of the AG36 grenade launcher for the British Army meant that the 51mm mortar was being phased out.

[JasonC]

US automatic grenade launcher. Meant as a crew served weapon as well as for vehicle mounts.

http://www.fas.org/man/dod-101/sys/land/mk19.htm

US 60mm plan of issue (sorry for the caps, they were in the original) -

D. BASIS OF ISSUE: THE LIGHTWEIGHT, 60-MM COMPANY MORTAR WILL REPLACE THE CURRENT 60-MM MORTAR (M67871) AND 81-MM MORTAR (M68008) IN LIGHT INFANTRY, AIR ASSAULT, AIRBORNE, RANGER, AND MOUNTAIN RIFLE COMPANIES WHERE MAN-PORTABILITY IS NECESSARY. THE BASIS OF ISSUE WILL BE TWO PER COMPANY.

Notice, this was envisioned as purely a light infantry matter, for units that have to leg it from A to B. In general, US light infantry expects to operate from helos. More on problem with that below.

Marines still use 81s, an extended range type developed by the Brits, used at the battalion level (much like WW II) -

The M252 81mm Mortar System - this mortar replaced the previous Marine Corps 81mm mortar in 1986. The M252 is an adaptation of the standard British 81mm mortar developed in the 1970s. It is mostly commonly found in the mortar platoon of an infantry battalion.

US dismount 120s have replaced 4.2s in motorized infantry formations. They are Hummer carried.

D. BASIS OF ISSUE: ONE-FOR-ONE REPLACEMENT FOR THE 4.2-INCHES MORTAR (M68282).

The main US army mortar is the tracked 120mm in the heavy army formation, on an M113 carriage. (M121 model). There are 1200 of these in the force. They can of course be dismounted when emplaced use is preferred to mobile use.

The marine corps is experimenting with a rifled 120mm mortar.

Smart ammo for mortars remains a development priority but only experimental types have been fielded. The Brits developed smart 81mm rounds in the 80s, but cancelled the project later on. The Swedes (Bofors) have smart 120 rounds in service and for sale abroad. The US has development versions of smart 120s - lased, terminal IR, and GPS varieties - but has not yet fielded them in practice. No one has even looked at smart rounds for mortars below 81mm. The future of the arm is smart and larger, not small and unguided.

In Afghanistan, US forces praised their 60mm, liking them for their range especially (all of 3.4 km). This mostly reflects how light they are fighting due to mountain terrain. The organic weapons include plenty of items more potent and equal or better in range, but these have typically be left behind on actual tactical moves, as "too heavy".

Javelins, heavier mortars, air lifted 105s, Mk 19s and 50s, are all available. But in practice they take 5.56mm SAWs, a few sniper rifles, unguided and short range AT-4s, and a few 60mm mortars per company. With battalion level weapons typically left on base perimeter defense. To KO a mud hut, they use AT-4s from 200m. To KO an HMG bunker farther away than that, they call the air force. Not efficient in response time or targeting.

The mobility plan for these forces was supposed to be UH-60 helos. But in practice, helos have serious problems as lift in mountains above 10000 feet, and are quite vulnerable to enemy HMGs etc. (Larger CHs are used for marginally better high altitude performance).

Insertion points are therefore lower down and away from hot zones, and the men have to hump anything heavier up ranges that are daunting even for unencumbered men in peak physical condition. (It is not a rock climbing issue, it is just that every long move involves several thousand vertical feet to hike up, and down, and up again, etc).

[Michael Emrys]

And thin mountain air effects men who aren't adapted to it as much as helos. We should start recruiting Tibetans and Nepalese.

Michael

[Wartgamer]

The modern US 60mm is much more than a 'light mortar' (in WWII terms). Its fuse options, range and lethality makes it much greater than the WWII type light mortar.

[JasonC]

Horsefeathers as usual. A 1 lb bomb is thrown less than 2 miles without a guidance system. It is a weak popgun. They need them anyway because they left all the real weapons behind.

What they should have is a javelin crosshair on every enemy hut at 1.5 km, sniper rifles in every section, 30 caliber belt fed MGs for 1 km work, Mk 19s and 50s suppressing out to 2 km, on call 105 and 120 from helo'ed in firebases.

Instead they have a 5.56 SAW with 500m effective range, maybe a scoped rifle or two in the platoon, AT-4s and M203s if they can get to 200m but pretty useless otherwise - and a couple of 60s, which they therefore consider priceless, because they are the only thing they have that will hurt an enemy with a 14.5mm AA MG over on that next ridge, which to reach on foot would take a drop of 2000 feet then an equal climb, under fire.

[JasonC]

Michael - tell me about it. Extreme exertion at altitude makes my lungs feel like I've got emphysema. And that is just running a half marathon at 7,000 feet. They are twice that high. You can't really acclimate either - to my altitude sure, but not to stuff above 8-10k feet. You just won't be up there long enough, unless you enjoy dying of exposure. The base camps might get you used to 6-8k, but not to the real peak elevations.

[Michael Emrys]

I remember reading that the Tibetans, and presumably the Nepalese as well, not only have increased lung capacity for their body mass, but their blood cells are better adapted for the transport of oxygen. Same thing for the Andean Indians.

Michael

[Wartgamer]

Happens to anyone that goes to a higher altitude over time.

[Michael Emrys]

People in otherwise good health can adjust. They do not adapt, which is governed by one's genetic inheritance. They do not get bigger lungs and although they produce more red blood cells, the structure of those cells does not change.

Michael

[Wartgamer]

I can run a mile in the same time as sea level and I live above 6000 feet. I grew up at sea level.

Horsefeathers as usual. A 1 lb bomb is thrown less than 2 miles without a guidance system. It is a weak popgun. They need them anyway because they left all the real weapons behind.

Anyone have a clue what weapon Jason is talking about? A 60mm throws a 3 pound bomb?

[ May 07, 2005, 08:17 PM: Message edited by: Wartgamer ]

[JasonC]

The payload.

[Wartgamer]

Oh. Right. How many horsefeathers in a pound?

[Andrew H.]

Originally posted by Michael Emrys:

People in otherwise good health can adjust. They do not adapt, which is governed by one's genetic inheritance. They do not get bigger lungs and although they produce more red blood cells, the structure of those cells does not change.

Michael

If you usually live at sea level and spend a week or so at 8 or 10 thousand feet, your lungs and blood will become more efficient at processing oxygen and things will be much easier for you than they were the first day you moved above 10k. I think it's accurate to describe these biochemical changes as your body "adapting" to the altitude, even though this is not the same kind of adaption for which Sherpas, say, may have been genetically selected.

[Michael Emrys]

Originally posted by Lord Peter:

If you usually live at sea level and spend a week or so at 8 or 10 thousand feet, your lungs and blood will become more efficient at processing oxygen and things will be much easier for you than they were the first day you moved above 10k.

Right. I already said that, only I called it "adjustment" so we wouldn't get it confused with genetic adaptation. Clear now?

Michael

[Wartgamer]

yeah. clear. you sounded like an 'old-timey'.