I mostly just play the game. The Jackson outranges the Panther and the latter usually needs to seriously commit and expose itself if it wants to actually kill the Jackson, which of course is a risky business...especially so since the Jackson is much more agile than ie. a SU (no turret...). Even if it comes down to a trade, the US wins.
Edit: Just saw your playercard. Sry dude, dont confuse this for an ad hominem, but I suggest playing some Ost/OKW. Once you hit the sphere where US players know what they are doing, you are gonna have the strength of the Jackson amply demonstrated, believe me.
Parking right in front of the Jackson isnt exposing itself. Even in this Scenrio the Panther usually comes out on top. It may be risky to Chase it down into enemy territory but not AS risky as if the Jackson tried to do the same. That whole Good luck Penetrating and touching my massive HP pool frontally ability it has is very very handy against USF AT support.