How much towed artillery is still a viable option very much depends on the scenario. In airmobile operations ultralight 155 mm or light 105 mm guns remain the alternative to heavy mortars, ammunition supply remaining a key issue.
To cope with airmobility weight limits 155 mm systems are usually fitted with 39 calibre barrels, which means that their range with standard ammunition is slightly in excess of 20 km, well enough for such operations. Last generation towed gun-howitzers are fitted with 52-calibre barrels, which give them a longer range. How much the towed solution is still viable when confronted to truck-mounted systems with similar ordnance is matter for conjecture, some armies having given up the gun plus truck solution to put the gun over the truck itself. Numerous 155/39 mm systems remain in service, even in first tier armies and in most cases limited budgets are the main reason behind that choice.
The Indian overarching need for artillery includes also a towed gun-howitzer. Two 155/52 mm systems took part in trials that ended in fall 2014: the Nexter's Trajan and the Elbit Systems Athos. Meanwhile a shorter barrel competitor, an evolution of the Bofors FH77B developed in India and featuring a 45-calibre barrel with a 38 km range, also carried out its latest trials following technical problems encountered in 2013. The Indian Army ordered 116 such guns from the Ordnance Factories, to which 300 more guns might be added. The TGS (Towed Gun System) segment will be the bigger slice of the field army rationalisation plan, as some 1,580 systems should be acquired by Delhi. India recently lifted the ban on various defence contractors, among which is Denel of South Africa, another artillery producer, although this company was more involved in heavier systems. Besides the need for "heavy" field howitzers, Delhi also planned to acquire 145 M777 ultralight howitzers; the programme was delayed motivating BAE Systems to close the ULH production line, which together with the increasing value of the US dollar considerably increased the potential budget for that operation. However, in January 2015 BAE Systems offered to transfer the entire M777 assembly line from the United States to India to partly overcome those issues and to ensure an even higher customisation of the howitzer. How much this will allow to restart the acquisition process remains to be seen.
The M777 was developed to provide airmobile 155 mm artillery to the US Army and US Marine Corps, complementing the former and much heavier M198. The weight limit was placed at 10,000 lbs (4,218 kg), and to remain within that weight titanium and aluminium alloys were used. Given that the M777 has not been provided with an autonomous propulsion system; it can be sling-carried by CH-53E and CH-47D helicopters, the MV-22 Osprey and on board C-130s. A Humvee is sufficient to locally tow a howitzer, though a heavier vehicle is required for longer distances. The M777 can fire five rounds per minute for up to two minutes, sustained fire rate being two rounds per minute.
The initial M777 version was fitted with an optical fire control, the A1 configuration adding on-board power to feed a digitised suite that included an INS/GPS navigation and positioning system, a radio, a...