ISU-122/ISU-152

The ISU-152 was an assault gun based on the IS tank chassis, following the example of the SU series before it. It's role was to bring the biggest gun possible on a heavily armored chassis into the fight, rolling up to enemy hard points and using the sheer explosive power of the 152mm cannon to silence them. When 152mm cannons were in short supply the soviets experimented with mounting 122mm cannons on the spare chassis, and the commanders liked it so much that they demanded more of them, giving birth to the ISU-122. These assault guns were big, bulky, and heavily armored; exceptionally tough targets for their German adversaries.

Flames of War

In Flames of War, the assault guns perform the double role of heavy tank and artillery support. Though their armor and training is worse than that of the IS-2, their firepower is equal and they are cheaper, allowing you to bring a unit of (still) relatively heavily armored vehicles with tremendous firepower for much cheaper. A unit, I might add, that in a pinch can double as a large artillery battery of heavy guns.

Overall, the ISUs are an interesting heavy vehicle. Where most other heavy tanks, such as the IS-2, KV-1, and even the Tiger rely on strong side/top armor and good assault values to assault and push back defending infantry, the ISU series relies on artillery barrages since their casemate nature and lack of machineguns leaves them vulnerable in close quarters. This may be ideal when dealing with infantry that are armed with gammon bombs or a large amount of AT weapons, where they can neutralize them from outside their effective range. If playing a heavy assault gun regiment, consider using the Recon by Fire card to line up devastating first turn bombardments and combine them with a solid assault element like the above heavy tanks or infantry to be able to clear up objectives that your assault guns have weakened in bombardment. The sheer amount of heavy tank hulls and high AT will go a long way to help deal with heavy tanks and the number of bombardments a regiment of these things has can make quick work of AT guns and infantry from relative safety.

Late War

ISU-152

The ISU-152 is an extreme vehicle. It has an extremely huge cannon with a 1+ firepower and AT13, but only has an extremely short direct fire range of 20". When this thing hits, it does big damage, but considering the short range and slow firing it won't be hitting a lot. Frankly, compared to the ISU-122 this vehicle is significantly more expensive for only a marginal boost in firepower and losses in range and penetration. If you wanted a devastating artillery bombardment, there are much more cost efficient ways to do it, and the vehicles with the long 122 are better in most cases at direct fire work. Overall, I personally struggle finding a use for this vehicle unless you want to bring the 8 point hero card.

ISU-122

Compared to the ISU-152, the ISU-122 is cheaper, has better penetrating power and range in direct fire on its guns, and only has a worse firepower of a 2+. While this takes away it's ability to lay down God-tier bombardments that waste everything unfortunate enough to be caught beneath it, it also makes them more capable in their actual role as an assault gun: driving up to enemy positions and blowing them up. If you had just wanted an artillery unit, there are much cheaper ways to go about it after all! 2+ firepower is still 2+ firepower, and this thing is going to hurt whatever it hits, at 8" further out nonetheless! Take it as a cheaper IS-2 for hunting tanks and antitank guns: it's armor and skill are slightly worse, but they have the same firepower for significantly fewer points.

In Real Life

The ISU-122 and ISU-152s were assault guns based on the IS chassis, replacing earlier types based on the KV chassis. They were armed with massive guns meant for bunker busting, but were found to also be effective against German tanks, the explosive force of the shells able to shatter the by then poor quality German steel. This power earned the ISU-152 the moniker of "Beast Killer". Of course, these fantastic properties had major tradeoffs, the lack of turret made aiming awkward, and the large guns were slow to reload taking around 20 to 30 seconds, which is why it ultimately was mostly used to destroy forts and support infantry. Like other prolific Soviet designs, they were upgraded and sold to friendly powers like Eygpt, which used them in their wars against Israel, or Iraq, who used them even in the Gulf Wars.

Soviet Forces in Flames of War
Tanks:	T-70 - Valentine - M5/M3 Stuart - M3 Lee - T-34 - KV - Churchill - IS-2 - Captured Tank Platoon - T-28 - BT-7 - KV-2 - T-26
Transports:	M3 Scout Car - Universal Carrier - SdKfz 251
Infantry:	Rifles - Motor Rifles - Penal Company - Storm Group - SMG Company - Engineer Sapper Company
Artillery:	Katyusha - 152mm Artillery - 122mm Artillery - 76mm Artillery - 120mm Mortars - 82mm mortars
Tank Destroyers and Assault Guns:	45mm Anti Tank - 57mm Anti Tank - 76mm Anti Tank - 100mm Anti Tank - SU-76 - SU-85 - SU-100 - SU-122 - SU-152 - ISU-122/ISU-152
Recon:	Scout Platoon - BA-64 Platoon - Armored Reconnaissance Platoon - Reconnaissance Platoon
Aircraft:	Il-2 Sturmovik
Anti-Aircraft:	ZSU M17 - DShK AA MG Platoon
Midwar Monsters:	KV-3 - KV-5 - T-43