to give more info :
(i had takken this from the reddit page of the person who had done reaserch on it , with colaboration of the museom where the turret courently resides , the post was made in october 2023)
" First, for those who may not know, the Meroka is a 12-barrel 20mm system that was originally designed in three variants: Naval (a successful CIWS), towed, and self-propelled (for use in land vehicles). One unique feature of this system is that it functions like a shotgun, firing the barrels in salvos with milliseconds of delay to avoid the resonance phenomenon, creating a cloud of bullets that dispersed at greater distances from the target. Another particularity was its reloading system, which was done pneumatically, so if a projectile didn’t function or was defective, it wouldn’t jam the barrel.
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In 1961, when the development of the BMR began, CETME (the company that created the Meroka) saw an opportunity to introduce their system into this vehicle, creating the self-propelled Meroka, a variant of the system for use in land vehicles. Alongside the self-propelled Meroka, a twin 20mm barrel turret was designed to create the BMR A.A., an anti-aircraft variant of the BMR. It was planned to mount these two turrets on the BMR 3560.2, a BMR prototype armed with a 20mm cannon and a TOUCAN turret. To achieve this, it was first decided to test the stability of the Meroka system on wheeled vehicles, which was done by mounting the system on an AML-60 Panhard [the second photo, you can see the turret on the back right dismounted just after the tests]. However, studies showed that the BMR might not be suitable for mounting the Meroka system, so a decision was made to create an aerial variant using the VEC chassis (a reconnaissance vehicle whose chassis is derived from the BMR and is often confused with the BMR itself due to its former designation as BMR-625 VEC). Since the VEC chassis was too narrow to accommodate the system, a special VEC chassis was built to house the Meroka system; however, it was never mounted and I have been unable to find photos of that chassis.
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In 1980, shortly after Chrysler S.A. created the M41E (a variant of the M41 Bulldog with a coaxial MG-42 machine gun and a more powerful engine that did not succeed), they considered creating an anti-aircraft variant of the M41. Initially, they considered arming it with Mauser cannons of 20, 25, and 30mm, but later, they also considered mounting the Meroka system. There is a discrepancy between sources here, as one source says that no drawings were made, while others confirm that there were drawings with the Meroka system mounted. This turret was supposed to be equipped with acquisition radar and fire-control radar.Neverless no prototypes were ever made cause the army dislike it. The reasons all these anti-aircraft variants failed, first the disappearance of CETME, but also the lack of investment in them, and the fact that the Meroka was not a good system to be used against anti-aircraft fire, as its effective range was only 2 km.
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Regarding the Meroka turret for the Pizarro that never was mounted, the turret located at the Infantry Academy in Segovia, I have not been able to find any information about it. If you want to see this turret virtually, visit this page (https://patrimoniocultural.defensa.gob.es/es/novedades/MuseoArtilleríaVirtual), where you can find it. You can also see the original photo where I found this turret on this page (Visita a los museos de la Academia de Artillería de Segovia - Noticias Defensa Galería)."
