Viability of Modernizing old Tanks?

[Marcus Aurelius]

Yeah, I was talking turretless, like a STuG. A more contemporary example (well, 1980's contemporary) would be like the ASU-85 airborne assault gun the Soviet Airborne had... but that is only an example of the concept; the ASU-85 was, IIRC, a PT-76 light tank chassis with a 76mm gun on it.

ASU-85 is a PT-76 with a 85mm gun. However a couple enclosed turret 85mm versions of PT-76 were designed, though only produced as sub variants in China and North Korea. The same 85mm gun also mounted on a BTR-70 but that was also not mass produced by the USSR. My understanding of the ASU-85 is that it had no turret in ordered to have a very low profile to fit in smaller aircraft and under choppers.

I remember the BTR-70 based tank destroyer 2S14 "Zhalo-S" actually had a newly designed smoothbore gun, basically a scaled down version of the 100 mm T-12 towed AT gun. Wikipedia claims the factory designation to be 2A62 for that gun, but there is no mention of the source. In any case, it certainly was not the older D-44 or SD-48 gun, which is quite evident from the pictures below, but I'm not sure if it was smoothbore or rifled. It appears to have both a bore evacuator and a pepperpot type muzzle brake. The project was apparently abandoned, because the penetration of the gun was deemed insufficient.

Here's a nice image from Kubinka. That gun is really long compared to the vehicle chassis and turret:



Another image from some boneyard:

[Sea Skimmer]

I remember the BTR-70 based tank destroyer 2S14 "Zhalo-S" actually had a newly designed smoothbore gun, basically a scaled down version of the 100 mm T-12 towed AT gun. Wikipedia claims the factory designation to be 2A62 for that gun, but there is no mention of the source. In any case, it certainly was not the older D-44 or SD-48 gun, which is quite evident from the pictures below, but I'm not sure if it was smoothbore or rifled. It appears to have both a bore evacuator and a pepperpot type muzzle brake. The project was apparently abandoned, because the penetration of the gun was deemed insufficient.

Well what little I've seen on it said it used existing 85mm ammo as well as new rounds; which made it sound to me like its just an evolution but I'm away from home for the weekend and my home PC monitor broke away, so I don't have my sources.

[Coyote]

Huh, I didn't know the T-55 was still good for up to 122's. Cool.

But the thing is, older MBTs are at best useful to upgrade for non-MBT functions. The Israelis modified old Centurions into Engineer vehicles by removing the turrets, putting up some armor, and making them open-air transports. Now they've done much the same with captured old MBTs, which they've turned into APC's called Achzarit, and some others called Namer. Remove turret, expand troop compartment, bingo.

As for assault guns, I'm a fan because assault guns can still be made low-profile enough to be air-deployable a lot more easily than tanks, but the sad truth is (despite my pro-assault gun bias) the only reason for an army to build & use assault guns today would be to suit a perceived need in their doctrine. An assault gun used for infantry support means that an MBT is released from such duty to go participate in some spearhead somewhere else.

Right now, we do have an assault-gun-ish type weapon, in the Stryker mobile gun carriage, with the pop-up 105mm gun. Not quite what I'm thinking, since I'd think that if you're going to go the assault gun route, you need to build it small. That (to me) is the whole idea, the trade-off from the versatility of the turret. I haven't paid attention to know if it is deployed, much less successful.

[Marcus Aurelius]

Right now, we do have an assault-gun-ish type weapon, in the Stryker mobile gun carriage, with the pop-up 105mm gun. Not quite what I'm thinking, since I'd think that if you're going to go the assault gun route, you need to build it small. That (to me) is the whole idea, the trade-off from the versatility of the turret. I haven't paid attention to know if it is deployed, much less successful.

There are plenty of light support or tank destroyer type vehicles. The Stryker MGS is just one of them and a somewhat more high-tech example than most others, but practically all reasonably modern wheeled APC chassis can take a turret with a 90 mm or 105 mm gun. If you need more firepower, there is the CV 90120-T, the Centauro 120 and the 2S25 Sprut-SD.

Low profile used to be a very big advantage when the primary ammunition types were relatively low muzzle velocity full caliber APCBC and HEAT, and range finding was either based on "guesstimations" or at best passive optical means such as stadiametric, stereoscopic or coincidence range finders. APFSDS (and APDS to a lesser degree) combined with laser range finders means that even low profile targets can now be accurately hit at long ranges. Consequently low profile design for armored vehicles is now considered a somewhat secondary concern, although it naturally still has the advantage that finding hull and turret down positions and concealing the vehicle from ground observation is easier.