I have an older (20 year old) Bushmaster A3 and a new Colt. You going to put back-up iron sights on your ORC?
That would be very cool to own an old Bushmaster, I would make sure I told everyone it isn't current Bushmaster though haha.
Yes, I almost purchased the Magpul MBUS But decided against it for now because of their disclaimer that their sights shouldn't be mounted onto a gas block due to heat issues. I looked that up and some people claim that the gas block can get hot enough to melt them so I decided against it.
I will probably get some troy industries battle sights (the kind with the diamond shape rear)
I also plan to put in a low profile gas block, and get a Nordic hand guard to free float the barrel. (held a gun with one on it and it felt great) If I do the handguard as my next project I "COULD" then use the magpul sights, or get the Troy sights first, and the handguard after. That I am not sure. I will likely go with a full length handguard and then get some sights, and at this time probably the troy sights.
I was actually very torn between getting that Aimpoint Pro, or some iron sights first, but I decided to go with the red dot because it makes me look more tacti-cool
I will be going to the range next week to zero in my optic and have some fun, If they aren't real busy I will take some video. I also want to experiment on where to place my optic on the rail (most people say as far forward as possible). I have tried a few positions, where it is at currently a few notches back seems most comfortable ...for now.