If it is indeed the old M196 tracer ammo for the M16A1, it will not be as accurate when fired out of the newer M16A2 rifles which has a different rifle twist rate.
1. None of the tracer ammo is as accurate as the ball ammo.
Plus it trashes your barrel pretty fast.
2. The faster 1 in 7 twist barrels of the A2s, M-4s and M-249s, will still shoot the older lighter ammo (55 grain M-193 ball or the tracer variant) just fine. They are just spinning like crazy.
It is the older 1 in 12 guns that do not stabilize the longer and heavier 62 grain ammo and the ridiculusly long new tracer rounds. We had key-holes at 25 meters using the new green tip M855 ammo while still trying to use older M-16A1 rifles for non-combat tropps weapons quals.
We were ordered to expend huge amounts of old tracer rounds for training and qualification purposes for over two years. Firing them through our M-4s, M-16A2s and M-249s.
Other than setting the range on fire at regular intervals, the ammo was just about as accurate as it was when being fired from the old M-16s.
Within the older range limitations of the older ammo and rifles...
We did note that the M-193 ball ammo would key-hole at 700 meters (about 50% of the impacting rounds) when fired through an M-249. The 62 grain M855 ammo still had a few key-holes at that range, but it was probably 5% or less.