I just got my first ACOG (TA31H) with the horseshoe reticle and just had my first time sighting it in today. I have it sighted in at 100 meters shooting XM193 out of a 16" barrel and it seems the BAC is off. I was making shots on steel at 100, 200 and 300 meters using only the big dot in the horseshoe. I had to use the tip of the 300 meter post in the reticle to make shots on steel at 500 meters.

Why is the BAC reticle so off?

Bindon aiming concept bac both eyes open shooting
Bdc is for 62 grain I believe

its not calibrated around a 55gr bullet from a 16" barrel is why

The bdc is based off velocity not ammo type.  Call trijicon and verify.
What was the temp?  My bdc is spot on with xm to 400.
When in doubt call them, they have well trained folks to answer questions from all kinds of people, like us Marines.

Wasn't the horseshoe reticles based on the dot being a 200m zero?