Uh, I'm probably going to sound like the village idiot here, but why cut the cases back?

I shoot .41 special all the time, rarely shoot .41 mag as it hurts. But I use regular cases.

A long time ago I clogged up the chambers in my 28 by shooting tons of .38 spl wadcutters in it and one day wanted to shoot some .357 mag and it would not chamber. After a good cleaning that was fixed but I still try to use brass that fits.

Besides it seems like a lot of work, and would also increase the pressure, which is ok in light loads I know.