Officers gained entry to an address in Lydia Gardens, Eastwood, shortly after 7am on Thursday morning (January 20).
The round of ammunition was found during a search.
A small amount of cannabis was also recovered.
A 34-year-old man and a 44-year-old woman were arrested on suspicion of possessing ammunition for a firearm without a certificate and possession of a class b drug.
They have both been released under investigation as enquiries continue.
Inspector Mike Ebbins, district commander for Broxtowe, said: “We are working every day to respond to our residents’ concerns and to take action against people who are involved in wrong-doing.
“Yesterday we showed we are listening to those concerns and carried out another proactive raid at a local address.
“I hope this incident will serve as a timely remind to others of just how seriously we treat the illegal possession of firearms and ammunition.
“I continue to urge anyone with concerns about suspected illegal activity in their neighbourhood to get in touch at the earliest opportunity.
“We will listen and take action when and where we can. Please utilise Crimestoppers or www.fearless.org.uk to report your information and all reports will be treated in the strictest of confidence.”
Anyone with any additional information about this incident is asked to call 101 quoting incident 72 of January 20.