140mm MBTs for Army : For nearly 40 years 120mm gun seems to have been the stable caliber of the main gun seen on all tanks, that were manufactured, but a drastic shift towards higher caliber of the main gun is starting to take place as Germanys Rheinmetall company today unveiled its latest main battle tank, the KF51 Panther armed with a huge 130/140mm caliber main gun. The tank reportedly weighs around 65 tons, which makes it lighter by 5 tons when compared to its predecessor which was armed with a 120mm caliber main gun.
The company claims that projectiles fired from a 130mm will be 50 percent more effective than the 120mm gun and will also offer a much longer range. French company Nexter is also upping the game and has started testing a massive 140mm main gun as part of the development of a future tank program. Nexter claims the weapon is 70 percent more effective than existing NATO standard 120mm tank guns.
Upgunning of the caliber of the main tank gun, seems to be done, so has to improve its armour penetration and range capabilities. India is among a few countries that are also planning to develop a new tank to replace its aging T-72B Main Battle Tanks, that can sit above current T-90S MBTs in the Tank hierarchy in the present Indian Army tank regiments.
DRDO has in past developed a 120mm rifled gun for the MBT Arjun program and it is not clear if Army will shift to the 120mm smoothbore tank gun, that it wanted for some years now. 130mm rifled or smoothbore tank gun can be developed locally for the Next Generation Main Battle Tank program if requested, but the Army that wants to start induction of Next Gen MBTs from 2030 onwards needs to decide on the caliber of the main gun now, so that there is adequate time for development and testing of the new gun.