Hmmm....

I don't see demolition guns (those 165mm "stubbies" that fired dustbin-sized hole punchers and obstacle crushers) returning anytime soon,

nor the 152mm (or anything similar in 6-ish inch caliber) gun launcher similar to the Sheridan (and lesser extent, the MBT70, although Russian tank guns from 100mm up have the option of a PGM, which many still argue are marginally effective, if at all).

 

The biggest problem with the Sheridan (later models did correct most of the chassis' mechanical problems) was that the 152mm system was just too overtaxing on such a light hull lacking any level of stability other than what the hull could absorb. That, and the facts that the combustible cases for the ammo were subject to cracking/brittleness under temperature extremes and was never corrected, the vehicle could only carry a mixed payload of 30 rounds total, and the Shillelagh missile's fire control left much to be desired (at range, the MGM-51 had plenty of warhead lethality: from what I've read, it used some kind of "octol shaped charge" which could head-on kill a T-72- I don't know if "octol" here meant an eight-sided cylindrical shaped explosive charge/liner, or some kind of explosive named octol, perhaps because of some kind of molecular layout in its makeup...?)

 

For its hull weight & dimensions, the Sheridan would actually be ideal for a system such as the NEMO (Hunnicutt's book Sheridan, A History of the American Light Tank, Vol 2 has several photos and descriptions of various Sheridan expirements, with modified hulls mounting anything from 105mm howitzers, the 76mm M32 series gun (M41 tank), and later developments included the feasibilty of mounting a 75mm ARES autocannon).

 

As far as "what battlefield worth does a breech-loading gun-mortar provide, that can't be provided by tank guns or howitzers?"...

I'll remind that, currently, the US Army's proposed FCS system will incorporate not only a direct-fire capable Mounted Combat System (damn weird name for a light tank armed with a 120mm gun)

 

...an indirect fire artillery piece, the Non-Line Of Sight Cannon, which so far appears to be mounting a 38-cal 155mm tube, (far inferior to many other nations' long range 45- and 52-cal tubes)

 

...and a Non-Line Of Sight Mortar,

which, by the Army's official FCS sight,

looks distinctively like a gun mortar mounted in a turret, not a system firing off a turntable thru roof hatches.

To me, that certainly suggests a direct fire capability, even if limited. And judging by the Army's fascination with all things automated in its FCS vehicles, it's most likely the NLOS-M will be the American equivalent of the autoloading NEMO.

 

As for AMOS or NEMO lacking precision: all mortars, and for that matter, all beyond line of sight indirect fire weapons, have a generally lower accuracy than direct fire high-velocity guns as tanks have.

But also notice: AMOS and NEMO are claiming to be capable with the current (and projected) 120mm precision-guided mortar munitions various nations are working on.

 

Yes, some gun-mortars must have purpose-built ammo: some of the Russian NONA-series tubes are incompatible (ammo wise) with other Russian 120mm mortars.

But the last time I checked out the AMOS and its autoloader (I'll search for the link), the ammo looked (to me, anyway) virtually identical to typical mortar ammo (no, I haven't seen the latest mortar bombs in a given nation's inventory, but...)

sorry I forgot this one:

Well, as far as I know, the Centurion AVRE 165mm  is still around in the British Army.

 

Back to the gun-mortar debate. Breech-loading mortar is good. Soviet 160mm heavy mortar and 240mm very heavy mortar are all breech-loading. Every mortar gunner hates to deal with failed shells, and breech-loading reduces the danger and all the difficulty dealing with that. Closed structure for better mortar crew protection is also great. NLOS-M might end up with a turrent, but it doesn't mean it will be used in direct fire support. It is hard to tell the future, and let's wait to see that in ten years.

 

However, from engineering point of view, gun-mortar is not really a well-thought idea. There is nothing wrong about the mortar part except it's kind of difficult to justify the spending on that particular system. We'll talk about that later. It is the gun part that make it unrealistic.

 

1. To achieve good and reasonable range, a shell must be launched in higher muzzle velocity about 400-800 m/s. Mortar shells are usually launched below the speed of sound, which will make effective rage abysmal.

 

2. To have acceptable accuracy, which is usually 1 mil at 1000m, most shells use spin stablizing. However, mortar shells are usually a big shutle-like thing followed by a spigot with fins on the tail. I really don't know how these mortar shells will fly in flat trajectory, and the result may be quite funny.

 

3. To make a gun-mortar system work well on the gun part, one needs to put 20-40lb of explosive device to at least 100m and no less than 1000m in flat trajectory. One had better have specially designed shells that can be fired at about 600m/s muzzle velocity and with some kind of stablizing method. The increase in muzzle velocity means increase in breech pressure and hence thicker barrel. It sounds me more like an improved T-55 rather than any gun-mortars.

 

Now, how will gun-mortar systems fit into existing land fighting organization? Let's say if we have 4 NEMO-Strykers of a platoon in each Styker batallion's fire support company, how will they be used? Will they be employed like sturmgeschutz or just like ordinary mortar carrier? Since they don't have start-of-the-art targeting system and unable to destroy even a T-55, they'll be mortar carriers.

 

By the way, Russians use 2S9 for airborne artillery support, which fits the category of "no tank and artillery" situation. French never actually bought MCB81 for their army. Instead, they bought wheeled gun carriers, like ERC-90, that can defeat T-55s and is C-160 transportable.

 

http://warfare.ru/?linkid=2460... shells for 2S9

And from online video I can find about 2S31 Vena system, I'd say that the system has a very low survival expectation for its crew. For a carriage that is heavy-machine-gun-defeatable, this is really a bad idea for propellant storage.

 

Also, from company AD on youtube: http://youtube.com/watch?v=EB4...

The breech loading mechanism doesn't seem to me like existing-or-developing-mortar-PGM compatible. Also, I still don't see how horseshoes, or propellant cartridges, are put on the mortar shell. Therefore I presume that the loader either put the round with full cartridges or has to prepare specific loads before putting them into the loader.

Says who a Stryker/NEMO won't have a state-of-the-art targetting system?

 

As you can see, the horseshoe-like things on the tail boom are propellant. I didn't see those in AMOS videos, and neither can I figure out where they put those propellant cartridges.

 

No matter it is Strix, Bussard or new US PGMM, they are all too long to fit into AMOS loading mechanism and have to be fed from the muzzle.

 

Targeting system means independent set of long range thermal image device, day/night TV cam and a laser range finder. It allows a single unit to observe and acquire targets. I didn't see those things on AMOS and NEMO. 

One has to remember: no typical optical/laser/IR targetting systems operate beyond line of sight,

and a mortar capable of firing >5-6 km is firing beyond line of sight (unless you're on a very wide open plain, or perhaps up on a hill looking down over a valley).

So most likely, these systems would be cued by forward observers, and possibly even FAC type aircraft and UAVs.

They could even be called up and directed by counter battery fire radars tracking inbound mortar fire themselves.

 

But for the closer ranges, it doesn't take a lot of complexity to install capable enough optical targetting systems: these weapons are not designed to be firing on the move against high-speed (in terms of cross country) maneuvering targets like MBTs (at least, not without PGMs), so complex sighting mechanisms are not necessary.

 

Not having any real knowledge of Scandanavian mortar team doctrine (Finland, Sweden, Norway.., or Slovenia for that matter, as they are purchasing the systems), I have no info on how they plan on aiming the AMOS or NEMO.

 

Besides, as far as any capability to fire the longer PGMs,

I'll leave that to the manufacturer's claims.

155mm artillery guns, even those with load-assist systems, can fire PGMs by means of manual loading.

So I suspect the NEMO and AMOS would have under-armor provision for the crew to at least manually load them, as opposed to exiting the vehicle and having to muzzle feed them.

Those automated 5" naval guns are minimally manned, but they obviously have been modified somehow to allow firing their PGMs like the USN's ERGM and Italy's Volcano (quite longer than average 5" shells, encased or not). Somebody obviously knows how to fire longer-than-standard ammo, so I don't discount the AMOS and NEMO.

 

I would suggest shooting off an email to Patria and asking them how they do it.

Haven't touched mortars for a while, and need to revive some of my memory regarding mortar operations.

 

Mortars are not long range weapons, and they are often used with aiming poles to identify coordinates. Mortar team leader needs to use compass and map to identify where the FO is and setup his mortar to line up with the FO. If the battalion CO decides dig in and stay for a long time, such as firing bases in Vietnam, then survey and planning will be conducted to setup an effective firing mission.

 

That's generally how WWII heavy mortar crews are doing, and that's the basics.

 

AMOS/NEMO system might use more advanced navigation and software to determine where the mortar system is firing at. However, no matter how fancy the system is, the crew must be able to fall back to the basics had the system failed, no matter it is due to EMP attack or plain lowest-bidder crap.

 

155mm howitzers and naval guns are different matter. Copperhead and Excaliber are no longer than rocket-assisted long range shells, and USN 5" naval guns are at least 1 deck deep into the hull. Mk.45 5" lightweight gun is even two deckers deep beneath the turrent. Naval gun shells are usually longer, heavier and more powerful than land guns of the same calibre.