I got turned into the 41 magnum a few years back. I really like the caliber myself.
Once again I listened rather than did, I was told the .410 was the way to go. Yes and no. All measurements of my 657 and Blackhawk hunter point more towards .411 and if I were to "fix" them as the thoughts go on cylinders I should open them up to .4115-.412.
I bought some different designs of molds and they show good promise. The 240 Keith just won't let them seat because of the front driving band being so long. The 215 RCBS mold is outstanding, not really a front driving band as much as it is there for a real crimp groove. I have an LBT and an accurate mold that the nose will slip into the throat when sized at .410.
In theory the bullet should be .411 at least, but it just won't fit. The .410 is working, no leading, good to excellent accuracy. So, "if it ain't broke don't fix it".
If it had issues I would open it up, just can't bring myself to do it. I doubt it would hurt it, but it is darn hard to put metal back once removed.
I find myself really liking longshot for this cartridge. For what it's worth, my ES runs 1-3FPS on a regular basis. I find it odd, and in a wheel gun to boot.
Jeff