Thanks for reaching out Mattithias! I asked my contact in Israel for the answer to your question. He said "Although it hasn’t been designed for it, some users told us that the M16 Lula, StripLula and the Range Benchloader load well the 300 Blackout." Now, to be sure, he's not promising that this mag loader will work with 300 Blackout, and neither will I, but you may find it works very well.