The project proposed by factory #172 consists of a 203 mm gun on the chassis of the mass production SU-152 SPG. The M-17 differs from the SU-152 in the following ways:
- Increased caliber (203 mm vs 152)
- Increased shell weight (100 kg vs 43.5 kg)
- Caseless ammunition
|Combat weight, tons||45.8||44.85|
|Ground pressure, kg/cm^2||0.81||0.8|
|Armament||203 mm gun||152 mm gun|
|Muzzle velocity, m/s||460||650|
|Propellant mass, kg||8.2||6.8|
|Shell mass, kg||100||43.5|
|Gun elevation, degrees||20||20|
|Gun depression, degrees||-3||-3|
|Rate of fire per 80 seconds||1||2|
|Barrel length with muzzle brake, calibers||22.6||46.3|
|Recoil length, mm||875||850|
- It is very possible to produce a 203 mm SPG on the SU-152 chassis using factory resources.
- High parts commonality with the SU-152 will allow for a rapid production of a prototype with minimal production costs.
- In order to reduce weight, reduction of armour thickness is allowed.
- The amount of ammunition on board is reduced by 4 shells (16 instead of 20 on the SU-152), which is insignificant, as the power of a 203 mm shell greatly surpasses the power of the 152 mm shell.
- A rate of fire of one round every 80 seconds is acceptable for this caliber.
- The placement of ammunition in the fighting compartment, convenience of loading, and ramming mechanism are satisfactory, but require testing with a physical prototype.
- The mass of 45.8 tons is the limit for this suspension, and the prototype mass should not surpass this limit.
- The 203 mm gun on the M-17 greatly surpasses the 152 mm gun in power.
- It is reasonable to produce a 203 mm SPG alongside the SU-152 for destruction of highly reinforced enemy fortifications.
- The mass of the M-17 SPG should not surpass the mass of the SU-152.
- In order to bring the 203 mm gun to self propelled mounts, I consider it reasonable to build a prototype of the factory #172 project with corrections by GBTU USA and provide it for GAU and GBTU trials for a final decision.