Sellier and Bellot

If it’s pistol, there’s no decision to make. For rifle, I think your question is something along the lines of are you gonna get shitty accuracy from that brass. It may not be as good as something like Norma or Lapua but it will work fine. If you have a lot of it, use it for sure. If you’re looking to break records, maybe opt for some better brass, but I’d say give this stuff a try
 
For a blackout I doubt youre after utmost precision so I would rock them if they meet a few conditions. Im reading up on them online and off center flash holes looks to be common so make sure you arent breaking decapping pins. The flash holes have also been reported to be too small so you could need the small decapping pin set up. The primer pockets have also been reported to be super tight. Any of those three would make it too much of a pain for me to bother with it myself unless I had no alternatives/time and buying other brass was out of the question.