Police attended a property in Bexhill after a man was reported to be threatening to self-harm with a gun, police said.
A police spokesman said they were called to York Road, Bexhill, at 4.55pm on Sunday (March 24).
Police said the man was detained by officers after being struck by a baton round – a large rubber or plastic projectile shot from a special gun – fired by specialist firearms officers.
There was no threat or risk to the wider public and upon arrest, an air weapon was seized by officers, police added.
The man was taken to hospital as a precaution for medical treatment, according to police.
A police spokesman added: “The Independent Office of Police Conduct have been advised.
“A 53-year-old man from Bexhill was arrested on suspicion of possession of an imitation firearm with intent to cause fear or violence.
“He remains in custody as of 11am on Monday (March 25).”