what riser height?

[BigNick73]

I got a flat top carbine I put together years ago. Well woot had some PFI red dots for cheap so I got one. Problem I didn't even think about is the rifle has the typical military A2 style front sight post and gas block, rear sights just as tall. The RD is a 33mm tube with what look like the lowest rings possible the tube pretty much sits on the rail almost no gap.

Anyone know how tall of a riser would give it a lower 1/3 co-witness? I'm thinking 3/4" but figure someone's done this before.

 

[DAUC]

I think you would want a 1" riser, http://www.cheaperthandirt.com/ARR372-1.html, for lower 1/3 cowitness. .83 will give you absolute cowitness. I think..

 

[BigNick73]

thanks! Got a couple on the way.