The only ammo I use in a rimmy is subsonic. The only way to know what is the best ammo for you is to do as above .. Buy a selection of ammo and see which works most consistently in your rifle. If it's accurate and consistent and you can find it to buy locally then you've found which ammo to use 
Bunnies don't need 'hard hitting' anything if you shoot them properly (in the noggin) as many a sub-12ft/lbs air rifle shooter will confirm. I cannot think of any .22 rimfire ammo (even shorts etc) that will not be delivering far in excess of 12ft/lbs at any range you can even see a bunny let alone place the shot on it.
Bunnies don't need 'hard hitting' anything if you shoot them properly (in the noggin) as many a sub-12ft/lbs air rifle shooter will confirm. I cannot think of any .22 rimfire ammo (even shorts etc) that will not be delivering far in excess of 12ft/lbs at any range you can even see a bunny let alone place the shot on it.


