...for me so I thought I'd pass this along:
I've been doing a lot or reloading in my Arizona garage since the weather has cooled off, some rifle but mostly handgun on my LNL AP. I've had everything dialed in nicely for some time now, press is running smooth as silk and ammo has been very consistent and precise. On my progressive I check about 5 - 10% of my rounds for accurate powder throw, mic for correct C.O.L., and drop them in my Wilson Case Gauge.
When loading 45 ACP the other night, I had a failure when I dropped a round in my Wilson gauge. That was very odd, I've never had a failure when plunking in my gauge before. I'm set for a 1.250 C.O.L., and .471 crimp. As I examined the round I noticed a slight bulge in the brass at the base of the bullet. At the mouth of the brass it measured .471, where the bulge was it measured more. The C.O.L. was correct and the bullet appeared to be seated squarely (BTW I do seat and crimp separately). I pulled the bullet and the Hornady FMJ RN measured a correct .451 in several places. Okay, so bullet is good, and crimp and COL were good. I'm thinking there must be a bulge in the brass-maybe something like those 40 cal "Glocked" cases. I ran the brass back through my die then dropped the case (no bullet seated) into my Wilson gauge--it plunked perfectly. So I seated the same bullet in that case and again it failed my Wilson plunk test again.
Still not clear what the problems is, I ran every round from my batch of 100 through my Wilson gauge and found 3 more rounds that failed the test. All four of these were Federal cases. I should mention that I drag a wide red sharpie across the head of my rounds before I shoot them so I can more easily recover them when I'm at my indoor range. These 4 cases that failed did not have any red residual on them. I have hundreds of other Federal cases that still have some red on the case head. So it is safe to say that these four failed cases were someone elses brass that I had picked up.
Even though I do not know the specific root cause of these failed cases, I was able to segregate them and assume that they were defective, worn out, or damaged by some other reloader or their gun. With this little experience I now run every single round through my Wilson gauge and If I find a failure, one that is subtle, I'll mark it so I can evaluate it at the range. Also this is causing me to rethink shooting others' "once fired brass."
And finally, this has given me great optimism for a few FTFs on my still new 1911. After my "Kimber" break in of 300 factory rounds, I've gotten a few here and there FTF. This weekend, my 1911 ran just perfect with my 100% passed Wilson Case gauge inspected rounds.
I have gauges for all my calibers, these are some of the best tools I've purchased.