"amx13 75/90mm gun ammo question?" Topic

the french amx13 originally came equipped with 75mm
main round pot-51 ?
later on they bored out the 75mm to 90mm
so question what rounds did they use in the rebored 90mm any details of these rounds appreciated
also was there a different style muzzle brake fitted or was it just rebored original

The 90mm was not a re-bore, it was an entirely different, low-pressure gun. The 75mm was developed from the KwK42 (as the Panther tank).

The 90mm gun is the same gun as the AML-90 armored car:

The DEFA D921 was the first 90 mm low-pressure gun to be mass-produced in France.[109] It was specifically designed for vehicles weighing under ten tonnes in mind, and the successful mating of such a large calibre weapon on the five tonne AML chassis was then considered a major engineering achievement.[26] This made an AML-90 exceptionally well-armed in proportion to its weight, and offered the advantage of easier recoil loads over conventional tank cannon.[21] The weapon was developed by the Etablissement d'Etudes et de Fabrications d'Armement de Bourges (EFAB) in the 1950s and partly modelled after the Mecar series of lightweight 90 mm KEnerga guns from Belgium.[109] Unlike the Belgian guns however, the DEFA D921 lacked a smoothbore barrel, instead utilising shallow rifling with a rather slow twist to impart a low rate of spin to the discharging projectile.[109] Its ammunition was also fin-stabilised, but improved on the Mecar ammunition by incorporating the fins as a direct extension of the individual shell, making it much shorter.[109]

As mounted on the AML-90, the D921 has an elevation of +15° and a depression of −8°.[105] It is provided with a co-axial 7.62mm machine gun to the left of the main armament. The turret is traversed by rotating the gunner's handwheels, which are not power assisted. Cranking the turret through a full 360° takes approximately twenty-five seconds.[105] A total of 20 90 mm shells and 2,400 rounds of machine gun ammunition are carried. The 90 mm high-explosive anti-tank round possesses a muzzle velocity of 750 m/s and will penetrate 320 mm of armour at an incidence of 0°, or 120 mm of armour at 60°.[6] The high-explosive round has a muzzle velocity of 650 m/s.[105] These rather low velocity performances, although suitable for close combat, make hit probability poor at extended ranges and proved to be a serious handicap when fighting tanks.[110] Combat experience during the South African Border War and the Six-Day War proved that the AML was decisively outranged by both the T-34/85[110] and the M48 Patton, respectively.[111] Its rather austere fire control, with optical ranging based on the crew commander's estimates, was also problematic.[105] The vehicle is unable to fire on the move, since its transmission cannot absorb the recoil of such a large gun while in forward motion and suffers excessive wear as a result.[112] Nevertheless, during at least three conflicts the AML proved capable of knocking out main battle tanks, often by attacking from the flank or rear.[39][53][113] The heaviest armour destroyed by an AML-90 was likely a Libyan T-62 during the Toyota War, in March 1988.[39]

old age got my tanks mixed up thinking of rebored gun on m41c walker bulldog on amx13
jkinder6 you answered my next question thanks