Hey guys. I don’t post here much but thought I’d show off my second 6450. I bought one a while back and sold it. Going this one last week for $1,000. Not bad considering what Gunbroker is asking for them. Anyway, just a question. This one is destined to be an SBR with 10.5" barrel. I want to keep the A1 upper but would like some kind of red dot optic or even a small power scope. What kind of options do I have? What have y’all done? Anyway, here’s an obligatory pic for ya!
Not many good options. The flat top is much easier to scope.
Google “carry handle scope mounts”
There are two basic options.
OR
I have the top one and it sucks. Won’t stay tight. And I hate to use loctite on it. Wish there was a better option besides the carry handle ACOG. What have some of you used and what optic?
Trijicon makes one. A bit pricey, but works well. 
Here’s a link to it. http://www.opticsplanet.com/trijicon-rx0110-reflex-65-moa-amber-dot-sight-m16-mount.html
Here is my original 6450, top pic.
Bottom pic is SBR’d with an RRA 10.5" upper.
Did not scope it, but it shoots accurately as it sits.