Many of the canon de 75s were converted into anti-tank guns, although the French army was unhappy with them as they were heavy, large, and not nearly as stealthy as smaller AT guns.
test of the M3 75mm gun on the M8 Chassis for a mobile solution
German conversion of captured 75mm guns, place on Pak 38 carriages
|Designer||Albert Deport, Etienne Sainte-Claire Deville, and Emile Rimailho.|
|Mass||combat: 1,190 kg (2,623 lbs)|
travel: 1,270 kg (2,800 lbs)
|Length||4.65 m (15 ft 3 in)|
|Barrel length||2.58 m (8 ft 6 in) L/34.5|
2.72 m (8 ft 11 in) L/36.3 (without muzzle brake)
|Width||1.85 m (6 ft 1 in)|
|Height||1.05 m (3 ft 5 in)|
yeah, that's bigger than this
|Variants||SA-L mle 1935: a shortened variant used in tanks and armoured cars such as the Panhard 178.|
SA-L mle 1937: a lengthened 77 caliber derivative designed by the APX with a much lighter 300 kg (660 lb) carriage
|Mass||480 kg (1,058 lbs)(modèle 1934)|
|Barrel length||1.8 m (5 ft 11 in) 72 caliber|
so yeah, 25mm is smaller than a 75mm gun
Problem is, Penetration
German tests :
The test was carried out 1/8-1941 with a 2,5cm KwK 121(f) by HWA on a 120 kg/mm2 armor plate (source : "Kennblätter fremden geräts heft 8a, Munition bis 3,6 cm" Released in Berlin 1941).
100 meters = 47mm /0°
500 meters = 40mm /0°
1000 meters = 30mm /0°
100 meters = 35mm /30°
500 meters = 30mm /30°
1000 meters = 20mm /30°
100 meters = 18mm /45°
500 meters = 16mm /45°
1000 meters = 15mm /45°
Panzer IV Ausf.D
The side and rear armour of the Ausf.D was increased from 14.5 mm to 20 mm, somewhat improving its survivability.
The front hull and superstructure was built with 30 mm thick face-hardened armour. In February 1940, 30 mm thick applique armour plates were bolted or welded to the front superstructure and hull bringing the armour protection up to 60 mm thick in these areas. Also 20 mm applique armour plates were also bolted or welded to the sides increasing the side armour in the centre to 40 mm thick. The last 68 Panzer IV Ausf.D tanks had 50 mm thick front hull armour instead of the original 30 mm. The increased thickness of the armour increased the weight of the Panzer IV Ausf.D to 20 tonnes.
The French 75mm AP, depending on the Model, mostly dated between 1900 and 1918, and at best could penetrate 68mm. And after 1940, the Germans found millions of rounds for the 75mm, and this could fire all types of ammunition, not just AP like the 25mm