I think when we have a volume of experience, we can come to some reasonable conclusions but I would caution sometimes that the conclusions are not always correct, and I’ll attempt to show that.
.327 Federal is a fairly new cartridge and so it’s been in the last 10-15 years that I’ve gathered all of my experience with it. All of my brass has come from ATK, or the former ATK, which is to say that’s it has come from Speer Gold Dot and American Eagle factory ammo. And this is a 45k psi peak cartridge. With all of this modern brass and all of it from THE same source, I can tell you for certain with the ATK/Federal/Speer .327 brass, the nickel absolutely splits more than the brass. Hands down, not close.
In .38 Special I have nearly 40 years of brass and it’s whole lot of brass. As .38 Special was the first metallic I’ve ever loaded… boy, I’ve loaded a LOT of this cartridge. Many tens of thousands for sure. My R-P nickel brass is split city. My Winchester nickel .38 Special rarely splits, and I’m quite sure that my supply of each is mostly many decades old.
More than ten years ago I came in to a huge supply of S&B brass in .38 Special, non-nickel, and I can tell you that this stuff splits very easily.
I also use a good bit of .357 Magnum brass that is nickel… again, a lot of Winchester here, and much of this brass I’ve definitely had more than 20 years and it’s very rare that any of it splits.
My conclusion based on what I’ve seen is that if I were buying new brass and looking for longevity, I would pick brass over nickel if the comparison were same headstamp. But my answer changes if the offer is a great brand of nickel versus a budget brand of brass.
As for the old “wears out dies quicker…”, I can only tell you that I have quite literally used
ONE single carbide sizing die for every round of .38 and .357 Magnum I have ever made, and this goes back to the fantastic summer of 1989. That’s a Lee carbide sizing die, and it’s still doing a fine job. While I cannot specifically tell you how many rounds of .38 and .357 have been through it, I do know for certain that I’m past 200,000 loaded rounds across all that I’ve made… and I have never worn out a carbide sizer from the one die maker that has the MOST dedicated legions of detractors in the history of handloading.