If it has a PNP headstamp, it could be a special run of ammo manufactured for the Philippine National Police. The Philippine National Police (PNP) briefly used South African manufactured ammo as well as Norinco ammo (which gave them problems with too much build up in the gas tube) in the 1990s. Prior to that, the PNP used WCC, LC, Pong San, and RPA (Republic of the Philippines Army). I was told that Norinco subsequently improved their ammo by using a different powder.
The PNP now uses WCC and BMP (Bataan Munitions Plant) which replaced RPA. BMP uses US components, and assembly of the bullets are made in the munitions plant in Bataan which was formerly the RPA plant.
Both the PNP and the Armed Forces of the Philippines use M193. No plans yet of switching to M855 ammo.
If you come across SB ammo, never, ever use them. They're terrible. Primers have come off the casings, and some primers managed get lodged into the gas tube.