its my understanding "nitriding" is a treatment to exisiting materials so it doesnt change its dimmensions ....chrome is a coating......i am a shooter and nitriding barrels are considered more accurate due to not adding material to the machinging.......chrome is what you will see in military rifles that can go full auto and take more abuse but are less accurate ..........i think both are good protectants ........and nitriding is a cheaper process .....no clue which would be better on a cylinder rod