GSI International, Inc.

I purchased 500 pieces of their converted 300 blackout brass, stock# [redacted]. Shipping was prompt and the packaging was satisfactory. The headstamp is dominantly Lake City with a minority of WCC. After inspecting each piece of brass, I was pleased to find that the good folks at GSI International included slightly more than 500, closer to 520, and that only one of those was split and had to be discarded. A few others were slightly dented but the resizing die took care of them.
I loaded 20 rounds and headed to the range to perform a functional check and was dismayed at the results; over half of those rounds would not chamber without help from the forward assist. I then ran another 20 pieces through my resizing die and saw an immediate difference. The shoulder was better defined and slightly pushed back. Those rounds fed and fired without issue. I then resized the remaining brass. It was not a problem considering the primer pockets were already swaged for me and I really dislike that process.
Overall, I am pleased. I consider the price paid to be reasonable compared to the cost, time, and effort it would have taken me to convert my own brass. I plan on this batch lasting me a long time, but when it wears out, I sure hope GSI International is still selling it because that is where I will go first.