Many of us tend to pick up a few empty brass cases while at the range. I myself tend to look for .308 empties that are reload able. Sometimes I get lucky and find a couple handfuls and some times I dont get any.
I bring the ones I find home and give them a good cleaning then a good inspection. Some of the things I find with differing types of brass are the rim may be thicker then most and the size of the flash hole can differ. Twice I have had stuck empties in my Howa and they both are CBC brass, which has a slightly thicker rim and the extractor has a hard time grabbing onto it. So these I save to use in my Cetme, which will fire anything and throw it out.
The flash holes I want all the same size so ignition is consistent. If I see the flash hole is smaller I will drill out the hole to the same size hole as a standard Winchester case.
Sometimes I also find some brass that the head is slightly tilts and if you stand the empty case up on its head the case tends to lean some, these I throw away, there has to be a reason they are like that and I am not going to take any chances.
Military surplus brass tend to be a tiny bit thicker then commercial brass so I tend to clean, resize them and trim the case mouth thickness so they will give a closer consistent performance as the commercial brass does.
Lo there do I see my Father...Lo there do I see my mother and my brothers and sisters...Lo there do I see the line of my peoples back to the begaining...Tho they do call to me...They bid me come take my place among them in the Halls of Valhalla...Where the brave may live forever
Long distance..The next best thing to being there, if you are anywhere between 100-700 yards my Howa and I own you and will choose your time of death. opaww