IMI/OTO Melara 60mm

[icy matrix]

In the late 70's, OTO and IMI collaborated to produce a rather impressive gun.
It was a 60mm cannon with penetration on par with the 105mm L7 firing APDS, although that gun did get improved ammunition. Still, a very potent gun, especially for the calibre.

It was intended for lighter vehicles, such as IFVs and retrofits of older vehicles, and indeed found its way onto a whole slew of vehicles.
The two companies did part ways, but both continued with the gun in their own way, with IMI's seeing some service in South America.

This weapon is one that I could comfortably see on both WWII and CW. The latter is the obvious home for it, but late 70's is within our WWII timeframe.

The first one is an Italian IFV prototype, the AV-90. A development of the C13 APC, it was developed as an IFV in the 1990's in collaboration with Germany. Like most designs of the period, it could be fitted with a whole range of turrets and guns, but the one that reached the prototype was the Italian 60mm HVGS. The vehicle wasn't adopted, with the Dardo being preferred.

Speaking of the Dardo, at an earlier stage the 60mm was considered as an option too.
As I understand it, this gun continued to be proposed for a long while afterwards

[icy matrix]

The 60mm was used in a whole bunch of retrofit projects, with varying states of adoption.
The M24 Chaffee was reasonably common in South America, and as such was a target for modernisation.

Urgh, the above is a Bulldog. This is the Chaffee.

Former M-50 and M-51 Sherman's were also converted to the M-60 standard

And because of reasons, even the M3 Stuart was a candidate.
https://tanks-encyclopedia.com/x1hvms/

An Israeli M113 was modified to be used as a prototype of the system. This turret design would later be fitted to a Marder and BMP chassis.

The Marder MICV was trailed by Germany with the intention of upgrading the Marder fleet as an interim before the adoption of the Marder 2.

The gun was effective, with an autoloaded RoF of 30, but the 35mm autocannon of the period could carry twice as much ammunition.

The BMP version

A Polish BWP-2000 prototype armed with the 60mm, specifically the Italian.

I don't know the exact timeframe, 90's-2000's.

[icy matrix]

There's two additional vehicles that I am aware of, but unfortunately they're wheeled.

First is an early Centuaro and the second a Fiat armoured car. Because of the current state of wheeled vehicles, I haven't included them.

It's also worth mentioning that the Israeli and Italian guns had different autoloaders. The Italian was able to fire at about 30 RPM from what I have seen, and the Israeli at 100. However, the examples fitted to the Chaffee and Sherman are manually loaded.

[sturdy marsh]

Wheeled CW tanks, dosent sound bad

[fleet galleon]

I think the 60mm HVMS in its 3-shot auto loader configuration could add some new flare to cw especially the Sherman and Bulldog versions.

IF they had Sherman and Bulldog versions.