Fixed it... here is what to change. Basically one character.
Open effectSequences.txt
search for the entries:
[AT_76.2mm_01]
0.0 ART_Shell_Light 0
0.0 AT_76mm_01 0
0.7 ShellCaseSmall 1
0.9 BarrelSmoke 0
1.0 hit
1.4 ART_Shell_Light 0
1.4 AT_76mm_01 0
2.3 ShellCaseSmall 1
2.5 BarrelSmoke 0
1.0 damage
[ART_76.2mm_01]
0.0 ART_Shell_Light 0
0.0 AT_76.2mm_01 0
0.7 BarrelSmoke 0
1.0 damage
Swap the two headers marked in red. Or put the letter R into AT and delete R from ART


You could change that in data.csv but way more to edit and you can make typo and the game won't load.