PN. Post 1978 the delivery profile for the 900 LB WE 177 from a Vulcan was 300 ft and 300 kts. That is what the crews briefed and practised. I guess some crews flew their own profile to expedite their egress but the 'authorised' release speed was 300 kts; QED the ac was 2.5 nm from the point of detonation.