I have an LMT M4 upper (w/ fat M4 handguards) with the LMT BUIS, and my new Eotech 552 (with Accucam) wont fit on the rail while the BUIS is mounted, since the front hits the handguards and the rear touches the the BUIS, preventing it from locking down by just a hair.
To mount it, I would have to move the BUIS back one slot, which puts its rear edge beyond the end of the charging handle (I normally have its rear flush with the rear of the reciever).
What's the lowest/cheapest riser solution out there for this problem?
Kharn