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For the rear sight I use ARMS #40L, it fits under all my scopes.
Front sight I have a PRI rail mounted flip up, it's a bit bulky but I like the hooded style sight.
My Matech BIS works for me. It's pre-zeroed from 200-600 yards and deploys quickly. It's kinda hard to find though and most of the ones offered on EGhey are stolen U.S. property.
+1 on the Troy BUIS. Works well over here, no issues at all. Dust was a concern at the start of the tour, but keeping it clean was the key.
YMMV,
Hoddie.