This is an interesting topic, first off it was Boots Obermeyer that developed the 5R rifling(5 standing for #of grooves and R standing for Russian). It is a cut rifled barrel, other companies also make the 5R barrel such as Krieger and Bartlein they are also cut rifled as Boots would have done it. Other companies that make the barrel only button rifle them call them a 5C such as Broughton.
To me the Remington 5R is a counterfeit, guaranteed not cut rifled.
I own two 5 groove barrels one an R and one a C, biggest advantage I can tell is that they don't blow up bullets like the 3 groove barrels they replaced.
they are accurate but don't clean any easier than any other custom barrel.
