An 18-year-old woman has been arrested on suspicion of possession of a gun.
Police officers affected a warrant at an address in Broadfield, on Monday (September 23), followed by a further search at an address in West Green.
During the search a gun was seized and an 18-year-old woman was arrested on suspicion of possession of a Section 1 firearm.
She has been bailed until October 25 pending further enquiries.
A spokesperson for Sussex Police said no one else is being sought in relation to the offence at present.