This may sound quite difficult at first but it actually really isn't.
The key is the Qirex Prototype ship. This ship comes equipped with a cannon system which gives you unlimited cannon ammo, turning this trophy into pretty easy work. The down side is that in order to unlock the Qirex Prototype you first need to reach level 30 to unlock the Prototype challenge that you'll then need to pass, hence why the ratio is probably so high. Once you've done that though the rest is relatively quick and easy, although it still may take you a few tries to get it done.
The event you'll want to do this on is the very first race of the 2048 season, Empire Climb (no weapons). This race has no weapon pad pick ups so the AI won't be able to fire at you or regenerate their health, while you'll be able to casually go about taking them down with your cannon. I basically stayed behind the pack and worked my way up one by one. Try to focus on taking one ship down at a time if possible. I found that seemed to work best. Also, try to save your bullets for when you're on a straight and directly behind, rather than firing while going around a bend. If you find you're constantly falling short by 1 ship though you may need to take some risks and try to get some bullets into them while turning. I found in the end I had to do that. Occasionally, a ship may blow up by hitting a wall, so just be aware of that and make sure you've definitely taken each one down yourself.
Good luck! It shouldn't take too many tries to get :)