7.62 x 51 belt 9:1 ball to IR/Dim tracer

I have never encountered this ratio of tracer to ball. I was told this was a loading for US Army Special Ops

PS H/S= @ LC 04 on the dim tracer

Probably for the M-134 “Minigun”. I imagine at 4,000 rounds per minute, at night, 1:9 tracer ratio is more than adequate. Just a guess though.

1DD

AKMS is right, this 9:1 ratio of ball to tracer M276 tracer ammunition is standard for helicopters armed with the M21 armament subsystem (two M134 and two 7-tube or 19 tube 2.75 inch rocket launchers) since the Vietnam era. Although the dim tracer round was developed to prevent permanent burns on image intensifier tubes caused by a conventional tracer round, this ratio also prevents the blinding of the low-light-level TV or image intensifier caused by the 5:1 ratio.

Pepper, check the third configuration from the top and note there is also a 14:1 ratio:

nice !

A picture of the metal box (M548 made by Conco):