[Bearkiller72]

Agreed. Same happened to me whilst trying the Me-410 mod, when it was first released (long before UI 1.0 :wink: ).
DF-tested it against a buddy, who didn't have the Me-410 mod and got the same results. Here's my answer to the same question, taken from the "Deutsch" section:

English: Right! Here's a smartasses' answer:
Yes, my friends, this is the reason, why CRT=2 is overdue in the Mod-world... People who still don't know the basics of the game engine - but to be frank, I had to learn this the hard way too, when trying out the (then) new '410 vs. a '109 in a DF melee. Lucky it was against a buddy and we were on TS, so we had the chance to communicate the problem and ponder about on the spot.
There's no object download in Sturmovik (think of the lags, if there were!), only skins get dl'd (if the server allows).
Your game reverts to what it "knows", what's stored locally (on your PC).
If somebody hosts an A/C you don't have installed (stored), you can't see it and if the A/C model uses other weapons but the original tracers, you won't have any damage effect, 'cause your game wouldn't know what to compile, but would show the original tracers, 'cause the engine finds them stored locally. Works the same vice versa. That's it.