It may be faded memories or it might have been luck... but I almost recall ammo explosions happened more often in TT.
I am pretty sure that ammo explosions happen less often for the player in HBS's BT when compared to Table Top BT, however I am not sure if it is more or less common when it happens to the OpFor.
Also, ammo explosions are more deadly in TT as well (when dealing with 3025 IS tech). HBS's BattleTech sort of contains the explosion to the location it occurs in (sort of like C.A.S.E.), where as no such protections are afforded in TT. In TT, C.A.S.E. must be equipped.
From what I understand, this is sort of a balancing move by HBS so as to not discourage players from running ballistic builds. I also think it might be there as well since ammo can not be dumped by the player in HBS's BT like it can be in TT.