Not operational afaik ...... Why can't MK1 fire it ??
Because it doesn't have the capability to do so .. Even mk2 prototype was having issues like smoke filling the compartments etc ... Google it buddy.
More news on mk2 prototype
http
://m.timesofindia.com/city/hyderabad/Poor-Israeli-parts-delay-Arjun-Mk-II/articleshow/29514617.cms
HYDERABAD: After the recent heartburn with Israeli counterparts in the Long Range Surface-to-Air Missile (LR SAM) and Medium Range Surface-to-Air Missile (MR-SAM) joint ventures which has resulted in delay of delivery in both these cases, Defence Research and Development Organisation, the premier defence research establishment in the country, is finding another of its major project, the Main Battle Tank Arjun Mk-II, hanging in the balance. DRDO is attributing the delay to the unsatisfactory functioning of some Israeli components, the major amongst these being the Laser Homing Attack (LAHAT) Missile.
According to official sources, almost 55 to 60% of the components and major part of the technology in Arjun Mk-II MBT are imported starting from the design to engine and the engine transmission system, gun barrel, computer-controlled integrated fire control system, the tracks, the suspension, and the Muzzle Reference System etc.
The German engine of Arjun Mk-I has again been integrated in Mk-II despite claims of an indigenous engine, as per the sources. When contacted, officials attributed this adjustment to the small order and that a separate plant for manufacturing engines cannot come up for such a restricted order. Sources revealed that Arjun Mk-II has a long way to go before being accepted by the Indian Army.
DRDO had recently launched its Arjun Mk-II for user trials in Rajasthan after integrating the same with almost 75-80 improved features including 16 major technologies as sought by the Indian Army which has already inducted 124 of the Arjun Mk-I tanks. DRDO has been developing Arjun MBT with help of its various labs led by Chennai-based Combat Vehicle Research and Development Establishment (CBRED) while Hyderabad-based Defence Metallurgical Research Laboratory of DRDO has developed the armour for Mk II version of Arjun. The development trials have been on for the past more than two years.
Apart from accuracy, smoke emanating from the Israeli LAHAT missile has been an issue of concern with both the developers as well as the users of Arjun Mk-II. "Israeli counterparts have been conveyed the issues and asked to rectify the problems at the earliest," was all Avinash Chander, secretary, defence research and development and director general, DRDO, could say.
Arjun Mk-II, the futuristic main battle tank, has been touted as one of the most potent combat tanks for the Army with unmatched automatic target detection and destruction while offering maximum protection to the crew in addition to impressive speed and maneuverability