50R BNC / TNC and 50R N types have the same outer conductor inner diameter and center conductor outer diameter BUT the tapered and reduced pin diameter is larger on N types than BNC / TNC . Thus while you can push a N male into a BNC or TNC female it will stress the female contact and my cause permanent deformation depending on the exact connectors.
BNC / TNC female is designed to mate with a 0.052 to 0/053" diameter pin Ntype is 0.063-0.066" diameter.
See MIL-A-55339A
Robert G8RPI.
