Ghost ring sights

Does any one know if there is ghost ring sights for a shot gun that mount to a pica tinny rail I am currently running magpul mbus but want ghost rings I have a black aces quad rail on it

There are several brands, to many to list.
Try googling rail mount ghost ring sights........

I get some that have the rail mount front but rear gets mounted directly to the shotgun

Here's one option.

http://www.midwayusa.com/product/627...unt-steel-blue

Or maybe something like this - betting they have a couple different options, but here's a starting point:

http://www.amazon.com/XS-Sight-Syste...st+ring+weaver