I don't know what's going on there, but in my install, the SD will p/u around 10k yds, the SD Improved will do about 12k yds, and the SV will do 14k, roughly - little more little less... unless the sea is rough, there's fog or rain, or any one of a number of different scenarios. One thing that I have seen happen is I'll get a "Radar contact, bearing 109" or whatever, see a little marker (map contacts on), and it then might drop-out, only to be replaced by a red triangle about 3 or 4 minutes later. "Sorry sir, tube went out!" Are you supplementing your SD with SJ? You almost have to, or use the APR, but if a plane doesn't have radar, then you're sunk also... (I know, bad pun)
The Tony in FotRSU carries 3x 100kg bombs (historical??) and 2x 40mm cannons (not historical). The 40mm was used since the 20mm in the game is NOT a cannon. There are also the wing MGs, and there are several "BombDummy" so that the plane will do multiple strafing passes on you. Definitely not something to tangle with. Do you have APR yet?
From the wunnerfull wunnerfull Wikipedia:
Armament
Guns:
2× 20 mm (0.79 in) Ho-5 cannon, 120 rounds per gun each
2× 12.7 mm (0.50 in) Ho-103 machine guns, 250 rpg each
Bombs:
2× 250 kg (550 lb) bombs
We'll look into the SD more though. I'm still editing Support folder files, s7rikeback is still working on NM and NK compliance, while vickers03 is working on Interiors compliance, so we'll be a couple days anyway before the next release.