check out my engagement vs the he100, a notoriously fragile aircraft, with many oil leaks (deadly) that just needs a couple of seconds of trigger to totally inutilize my frontline bomber.
You’re using the tracer belt, which only has IT rounds.
They have no penetration, deal very little damage to components and have (ironically) pretty bad fire chance.
If you want to accomplish anything with 7.7mm MGs, use AP-I. Or just AP, if AP-I is not available.
But you’re in luck. I just happen to find that there should be an AP-T round for French 7.5mm MGs.