I have a set of matte black heavy duty riser rings for flat top AR-15/M-16 and .50 cal rifles. Replace your heavy riser and rings set-up with these integral units. The rings are 30mm with 1" inserts and hex nuts. Attaches to a Weaver base or Picatinny rail. They are solid aircraft aluminum except for the nut and screw which are steel. $25 + $4.00 handling/shipping. Add $1.30 for insurance if needed.
I can send you a photo if you send me your email address.