Very good charts of headstamps and more. Worth looking if you're a Mosinite. http://7.62x54r.net/MosinID/MosinAmmoID.htm

I ordered some ammo the other day and recieved it today. Here is the link http://buygunsandammo.com/product/5-56-62gr-fmj-ss109-penetrator-sealed-brass-case/ The ammo looks good but I didn't recognize the headstamp. It says "5.56 SADU 13". I checked cartrdgecollectors.org but it wasn't listed...

My father was sorting through some brass we have and decapping/sizing and priming some. He came upon some that was very hard to decap and size. He tried a couple and it didn't work. He then cut one in half to find it was berdan primed. He also then realized that is was a steel case, just brass...