Tested taming extensively.

1. The acro does not seem to care about the damage output you are dealing while you shoot it, it cares how many times you shoot it and with what weapon. Use primitive to reduce the chances of killing it. Shotgun is best.

2. While it is doing the fake roar it will constantly regenerate health to full for the entire duration of the animation, this is a great opportunity to lay into it and force it back into shield mode.

3. If you do not shoot it during the false roar, it will become impervious to damage for about 5-6 seconds, do not waste your ammo during this time.