|Over at Jane's Defence Weekly,
there is an August 3 post:
"The US Army is planning to re-introduce production of the M119A1 105mm towed howitzer, the US variant of the BAE Systems RO Defence 105mm Light Gun, to meet a shortfall of 105mm artillery that will result from the Army's reorganization, service officials said. The Army is looking for 275 new howitzers: 111 for active duty units and 164 for reserve components." (full article is avaliable to subscribers)
Comparing the 105mm M119A1 howitzer,
to the 120mm M120 mortar,
What are the advantages the howitzer has over the mortar?
From what I see, the howitzer's RAP can reach 19km, whereas the mortar in US service does not yet have such an extended range projectile, limiting the mortar to just over 7km, roughly half the range of the M119A1 howitzer.
Also, the 120mm NATO-standard mortars have PGMs available (such as Strix, Bussard, and a few others), whereas the 105mm howitzers in US service do not yet have any PGMs (the 105mm STAFF round is not configured as separate-loading ammo for the howitzer, but could be implemented). Russian tube-launched missiles, by varying the propellant charge device, can be fired from 100mm guns (the 9M117 "Stabber"), including both the 2A70 of the BMP-3 and various Russian-built towed guns. Incorporating something like STAFF into the howitzer package could afford a self-defense weapon or an additional PGM for point targets. Even a new generation of PGM rounds developed for 105mm systems could present a defense contractor with another market to exploit, as several nations still employ 105mm artillery.
The US does utilize a self-propelled version of the 120mm mortar, the M121 (in the M1064A3 vehicle). But to date, no self-propelled 105mm systems are in US service, although UDLP is testing various concepts that may prove favorable to US requirements.
It is interesting that several NATO armies do still use towed 105mm guns/howitzers, yet very few still use 105mm SP systems. These countries do, however, utilize both SP and towed 155mm guns, and towed and SP 120mm mortars.
Perhaps, with the desire to field more 105mm fire-support weapons, the US may yet consider some form of 105mm SP system. There were conceptual studies for a 105mm LEO-based system incorporated into the Stryker 8x8 chassis (as is UDLP's V2C2 weapon mentioned in another thread) and perhaps an option for the FCS NLOS-C (which currently seems to be favoring a 155mm/L38 weapon).
Looking at the most cost-effective platform to develop an efficient SP mount for the US 105, (and this is entirely speculative), the LAV-25/Stryker 8x8 chassis and the stretched M113/MTVL hull are the two most favorable platforms in US inventory (or most readily acquired). Even reconditioning the older M113s (5 road wheels per side instead of the MTVL's 6) into the RISE standard with a slightly cut-down rear hull and incorporating a turreted 105, to vaguely resemble the 122mm 2S1 Gvozdika or the Abbot 105mm SP gun, would afford a shell-fragment/small arms proof artillery mount. This platform would easily fall under the US's stringent 20-ton weight limit for air-deployability. A four man crew would be sufficient for the relatively cramped M113 and Stryker hulls (considering a 105mm howitzer turret has just been installed). An autoloader would not be necessary for the 30-40lb 105mm shells.
Modifications to some of the turreted 120mm direct-fire-capable mortars might allow the turret to swap out one weapon for another (as an example, the Russian 120mm 2S31 Vena self-propelled system can function as both artillery or mortar, depending on the propellant charge used: higher pressures for longer-ranged artillery modes). These under-20-ton hulls would have no problem handling the recoil of a 105mm howitzer.
To go the more expensive route, there would be no reason a newer, longer ranged 105mm artillery piece could not be re-introduced into the M109-series hulls (the M108 was indeed the same hull, but mounting a 105mm weapon, and a considerably larger amount of 105mm shells). Such a system most likely will not see US service, though.
There is also the RDM MOBAT, a 105mm/L33 ordnance mounted on a firing platform at the back of a 4x4 cargo truck: such a concept would fit the US 4x4 FMTV ideally, with minimal expense to implement as opposed to developing a fully enclosed armored SP system. Affording the M119A1 such a mobile capability could prove ideal. Perhaps even a light-capacity knuckleboom gantry/crane could afford the option to remove the gun from the vehicle and place it onto its ground-based chassis/firing platform? The pedestal on the cargo truck could be configured for rapid removal, so the truck would be available as a