I have never been able to find RUM Nickel Brass to attempt loading, but I know in all my other rifles I use exclusively Nickel Brass if possible. For me it has allowed me to load marginally high velocities, it doesn't seem to grow as much as straight brass, and it lasts at least three times longer than straight. My 270 and 280 nickel brass both have 30+ loads on them and still showing little wear, whereas I tossed all straight brass for both calibers a few years ago because of sidewall thinning just above the base. I'm not discounting seaman's experience, I'm sure he has reason to steer clear of Nickel, but this has not been my experience. However, like I stated I don't have experience with RUM brass in Nickel so it is possible that is where the trouble lies.