Correct ID on the Hirtenberger rounds (these recently appeared on an auction site as ‘shortrange Vietnam countersniper rounds’ or some such thing).
FYI I have never had these rounds properly cycle any semiauto rifle (tried them in a Mini-14, 2 AR-pattern weapons and --!good old days!-- a Galil…bad luck I s’pose).
They are considerably more powerful than other SRTA-type rounds I’ve used. Shot at a steel target from about 15yds, the bullets actually stuck about 0.15" into the metal. Definitely not like the Winchester or DAG/RUAG synthetic-bullet cartridges.
Also, black ‘may’ indicate AP. Some manufacturers (IMI for instance) may use a color to ID a certain bullet weight, even with possible differing velocity or terminal performance. Example: IMI 115gr UZI Carbine, 115gr blacktip FMJ @ 1230fps from a Glock 19, vs. IMI 115gr Samson 115gr blacktip FMJ +p commercial ammo @ 1185 from the same weapon).