Ok,, Your Hornady manual #9 is outdated. They are into #11 right now. But I pulled a #9,, and they list Hornady XTP bullets as being .430,, not .431.
I would get the newest manual,, AND not look for max charges as my desire. I would look for the most accurate load. My first Redhawk .44 mag was VERY accurate with Hornady jacketed bullets,, with a load that was just one up from the starting load using IMR 4227. Blue Dot is a hotter & faster burning powder than what most of us who shoot 50-200 yds with big bore handguns. HS-6, 2400, 4227 Longshot are all preferred.
But back to the cases.
If I understand it correctly,, you are not getting severely crinkled cases,, but instead,, just getting a little bulge. When I first read this,, I envisioned the stuff I've seen folks have loading say,, 38-40,, where it's a thin bottleneck case subjected to easily crumpling & total wasting of the brass.
So,, again,, if I read this right,, you are just getting a bit of a bulge. I've seen this a lot in all kinds of calibers. It can be traced to thick case walls vs thinner ones,, or a slight difference in the expander of the dies. AND IT'S NOT AN UNCOMMON THING. I've seen different lots of brass from the same maker,, being loaded at the same time as each other,, and some get a little bulge,, & others,, none at all.
I don't really think you got an "odd" Redhawk.
Have you tried any factory ammo as a base line for testing things? Have you had someone else shoot your Redhawk using factory ammo to see if they get any different results than what you get?
Without going back through all the comments between us,, I don't recall mentioning what diameter bullets I use. But I never bother with anything if loading jacketed bullets,, as all the ones I've seen are .430. But if I'm shooting my cast & powder coated ones,, I do try & build my bullets to .001 over bore diameter. And yes,, cowboy dies can be used for loading jacketed bullets. You just have to set them up to do so.
NOE sizing dies,, or expander plugs,, again,, while they are designed for cast,, they should be capable of loading jacketed bullets. My experience with NOE has been only in cast stuff. And mostly their molds,, not any sizers or other stuff.
The slight bulge,, is not the same as a seriously crumpled case.
It's too bad you aren't closer to me,, as I'd gladly try & help you figure out what may be happening.