Neat timing on this thread because I have just begrudgingly started down the road of headstamp sorting my 9mm. That's the bad news. The good news is that 9mm is purely a utilitarian cartridge for me and has no recreational value (i.e., I don't take 9's out to the range to have a nice time; but only to get practice with them for carry/defense. Maybe twice a year) so there's no hurry. And . . . I have tons of factory ammo. (I've been handloading since '84, but never loaded the 9 until 2013 - and have still done only a smattering of work ups.)
Just to add some additional info: The "WMA" are from Winchester White Box "Nato" ammo. At least, that is the case (no pun) with mine. I bought four or five boxes (50) in 2013 (124gn FMJ) and they're headstamped "WMA 13." The WCC's and WIN's are from regular Winchester White Box - at least that is my experience. About 2013-ish, I also bought a bunch of boxes of "regular" (not Nato) Winchester White Box 124's & 115's; and they're stamped "WIN." Not "WCC," which is what I'm used to seeing in years past.
There have been times when I worked up a hot loading of 9mm and sorted a bunch of the same stamp on the fly for the work up. But any basic range ammo got mixed brass. It's time to get more formal with it and start sorting. I'll still used mixed for the range fodder; but anything more "serious" will definitely get like headstamps. As if I needed more stuff to do with my "spare time" *sigh* .
Just to add some additional info: The "WMA" are from Winchester White Box "Nato" ammo. At least, that is the case (no pun) with mine. I bought four or five boxes (50) in 2013 (124gn FMJ) and they're headstamped "WMA 13." The WCC's and WIN's are from regular Winchester White Box - at least that is my experience. About 2013-ish, I also bought a bunch of boxes of "regular" (not Nato) Winchester White Box 124's & 115's; and they're stamped "WIN." Not "WCC," which is what I'm used to seeing in years past.
There have been times when I worked up a hot loading of 9mm and sorted a bunch of the same stamp on the fly for the work up. But any basic range ammo got mixed brass. It's time to get more formal with it and start sorting. I'll still used mixed for the range fodder; but anything more "serious" will definitely get like headstamps. As if I needed more stuff to do with my "spare time" *sigh* .