I have a couple of black powder competition guns with stainless barrels I wanted to blue. One's a Krieger on a Cody Ballard and the other is a Ron Pense on a renovated Borchardt target rifle I've been working on. I recently have seen a write up on the nitriding process, which, among its other advertised qualities, leaves a black finish. It's pretty inexpensive compared to other processes I have heard of and the turnaround time is fairly quick. I was wondering if there was a downside, other than the fact that it isn't a blued effect, but a blackened effect.