How long do cases last with these light loads? It would seem that most of the wear is from the dies.
Yes, IF the dies are very tight and the chambers are very loose, there can be a wear issue on the brass, but the relationship in my pistols (5) and the older set of dies and pistol in this caliber which I learned on 35 years ago was just fine. I think the tight dies/loose chamber is the exception rather than the rule. And, if you run into it, with these light loads, I'd just start "half-sizing" the brass.
This is like what can be done for a rifle when you don't have neck-size dies but you want that effect, and you just run the cases in deep enough to get them to re-insert back in the chamber, but you're not full-length resizing them. This also re-sizes enough of the neck to give you good bullet tension, but keeps better alignment because part of the case is still close in size to the diameter of the chamber... This works good on a revolver, as long as the various chambers in your cylinder are pretty much the same. If you have one tight chamber, you could mark it, but with two tight chambers, doing this will leave you with a "four-shooter..."
Without this problem, and because I have many guns in this caliber that all eat my reloads, I prefer full-length sizing. I've got some cases with 20 reloadings on them, and they're fine. The place I wear out first is the mouth of the case from the constant bell-mouth & crimping (which works the brass even more than re-sizing).
Another issue which can develop from shooting these light loads is carbon smudging/fouling/burning on the OUTside of the case. These loads (worse the lighter you go) can develop so little pressure that they don't cause the case to swell up and seal off, so some of the burning powder gets between the case and the chamber wall and makes a hard, burned-on carbon smudge. This is unsightly, and if not cleaned sufficiently could scratch the sizer die (in theory -- I've always cleaned and lubed the cases enough to not let this happen, so that tidbit is not from personal experience). My recommendation is to just get some citric acid and wash the cases in that for 5-10 minutes, and the brass will come out shiney as new.
One last caveat about these light loads. I think it was said before, but when shooting JACKETED bullets, you must stick to higher loads to prevent sticking a jacket in the barrel. (The core often keeps on going and hits the target giving the shooter no clue the jacket has stuck...) With cast bullets there is no issue, because they are homogenous, and the other nice thing about cast lead is that it's lower bore friction means you can load them down lower than jacketed anyway and still get them to clear the end of the barrel.
