Robert,
The 9mm case is ever so slightly tapered. The chamber of a Luger, however, is almost straight-sided, with a slight "step" near the front of the chamber where it constricts to the diameter of the front of the case. A blueprint was posted on the Forum recently which illustrates this very well, you can probably find it in a search, or maybe John Sabato will ring in and tell us where he put it.
On the Lugers I shoot, at least, this leaves a characteristic ring near the front of a fired case, where it expands a bit into the cylindrical chamber (as you note) and the case is "dirty" where the powder blows back into it a bit.
When I started shooting Lugers I went through quite a series of practical tests to determine the best functioning ammunition. UMC was right near the bottom of the list, being nearly 100% disfunctional, right along with Speer and most of the gun show reloads I came up with.
At the risk of repeating myself enough times to bore everyone to death, I shoot Walmart Winchester, S&B, and CCI Blazer in three different Lugers (sometimes a fourth, if I break out my nickel-plated byf) with 100% reliability, somewhere between 400-600 rounds a month depending on how often I get to the range.
I use Mec-Gar magazines almost exclusively, and this probably has something to do with it (my magazine tests revealed that most of my original mags malfunctioned with anything I put in them).
I'm sure that some people reload for the perfection in it, my guess is that it can be pretty satisfying. 9mm ammo is so cheap that, in my shooting circumstances, it hardly seems worthwhile to take up yet -another- hobby.
--Dwight
|