Burris ff2 co witness for mbus riser size

[carlton wright]

I have a fast fire 2 and a pic rail mount. What size riser should I get to co witness with my mbus I am thinking of going with true co witness and not 1/3 is there a good reason why most people go for 1/3 co witness ?

 

[sparked1]

With flip up sights it doesn’t really matter much since they are backup to your primary RDS and are down most of the time. With non flip sights it becomes a question of whether you want more or less obstruction of your RDS. Personally, I like absolute co-witness with flipup sights for consistent cheekweld position.

 

[carlton wright]

That's what I am going for absolute co witness. Any idea what size riser i would need ?

 

[doublebarrelkungfu]

Found some discussion here: https://www.ar15.com/forums/ar-15/Mount_height_of_Burris_FastFire_III/18-586290/

There is also the Burris ARF3 Mount made for the fastfire 3, not sure if it works with the 2 but I used to have one with a fastfire 3 and it was nice