I have recently proposed a detailed suggestion to add a Romanian Mareşal chasseur de chars on local Russian forum, however, the voters and me have got a lot of questions on it’s gun performance.
I have used mainly ru-wikipedia and en-wikipedia for my sources, as I couldn’t find other ones where performance would be described.
English wiki states that the gun fired a 6,6kg 75-mm AP shell comparable to the German PzGr.39. What’s the most confusing is the information that it had muzzle velocity of 1 030 m/s, which is too high for a same L/48 gun and even APCR ammo (read Ru-wiki section below) for it.
One of the voters dropped an interesting comparison, which I have yet to prove with proper blueprint or especially a photograph. Here it is, featuring British, German, and most importantly Romanian AP called Costinescu, third from the left.
Spoiler
The question is, how could it reach 1 030 m/s while having smaller charge than German ammo?
Ru-wiki, however, says that Costinescu was an APCR shell. It may explain how it reached the 1 030 m/s, however, we are yet to know the real charge size for that shell. German analogues, L/48 guns, fired comparable shell, PzGr.40, with muzzle velocity of 990 m/s. As visible both in Russian article or in the picture I attached below, it had 495mm, or, better, 561mm long charge. Would it even be able to speed up AP or even APCR up to 1 030 m/s? Higly doubt so.
Would appreciate any knowledge on that topic, or links to old internet forums where it could be explained, or citations from documents and books if you own/share any. Thanks for your interest.