Police in Harrismith arrested a 21-year-old man on Sunday after he was caught allegedly transporting illegal ammunition to another man in Bergville, KwaZulu-Natal.
According to police, a "suspicious looking man was in possession of a carry bag" at Montrose shopping complex at the filling station on the N3.
"They approached and searched his bag," police said in a statement.
"They found 25 live rounds inside and the 21-year-old was arrested."
Following interrogation, the suspect led police to a house is Bergville where a second suspect, who was allegedly expecting to receive the ammunition, was arrested.
"He was found in possession of a firearm, one magazine with eight live rounds."
Both suspects are due to appear in the Harrismith Magistrate's Court on Tuesday.
Free State police commissioner Lieutenant-General Baile Motswenyane applauded officers for making the arrests.
"The proliferation of firearms and ammunitions has to be stopped and the only person who can do that is the patriotic citizen of this country by working together with the police," Motswenyane added.