Top level competitive shooters prefer coated solid steel rods or bare stainless steel rods; all one piece. In rifles, they use a bore guide in the bolt way. Everyone else uses what ever else is on the list of all types made that make's em feel good.
Bronze or brass bore brushes are also the norm with top level competitiors, no steel ones of any kind. Sub caliber nylon brushes make great jags for holding cleaning patches.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master