"Look at the size of that gun. I think we found Trotskaya's vibrator!"
The M-2000 is a massive self-propelled siege cannon built for the Mecharussian Armed Forces. With a bore diameter of two metres and a barrel length of some forty metres, it is easily one of the most massive guns ever built, if not the most massive.
Originally, the SPG was conceived solely as a propaganda showcase (under the designation Object 150), a means of boasting to the Western world that they could build such weapons. It was first test-fired in the 2140s and was never deemed practical for actual combat use, missiles being considered far more practical and effective for the same purposes it was intended for. Nevertheless, the guns found themselves drafted into World War IV, and they were used in the Siege of Northwatch. Two guns were deployed for use in the battle, firing massive fusion warheads capable of vaporising a good part of a city block with one shot, in the efforts of Operation Chirikov to break the walls of the Alaskan fortress-city.
Initially, the two Object 150s used in the war were due to be broken down for scrap after its conclusion. However, General Yulia Trotskaya gave these guns a new purpose. She specifically looked for a strategic-scale artillery piece to incorporate, and learned of Object 150 from outdated combat documents. Seeing it ideal for her intended purposes, she commissioned Ermakov Military Systems to build a battery of six for her regiment to use, under the production name M-2000, and even personally lent her hand to designing several new shells for it – such as a fearsome boron nitride-tipped bunker buster to use for assaulting hive-cities in her planned war against the Imperium of Sidhae. For logistical purposes, many IS-44 and IS-51 superheavy tanks were also repurposed into massive ammunition carriers (their large guns would be refitted to refurbished T-100 models converted into SPGs).
The new M-2000s were first trialled in the Second Helleon Campaign, along with the new shells. The mega bunker busters designed for the machine were especially effective at laying waste to Helleonic hive fortresses, but it was the giant cargo shells that Yulia conceptualised that the Helleonite forces feared the most. These oversized cluster bombs carrying fusion submunitions could wreak untold devastation on many square kilometres of land around ground zero, causing even greater damage than many thermobaric munitions and second in destructive capacity only to tactical nuclear warheads.