These samples were provided by emacstacticalshop.com but I do not know who manufactured them or where they can be purchased. They are supposed to be modern production projectiles made in the USA.
Teardown and examination shows that these bullets were light, only 110 grains, and produced averaged a velocity of 3,069 feet per second. They are loaded into old production steel cases, presumably for convenience and cost.
I fired them from the Mosin Nagant against several hard targets including steel and concrete blocks. Upon impact of steel they detonated with spectacular sparks and smoke. (See video) Like other incendiary I have tested they did not detonate against concrete.