Anyone familiar with Bushmaster barrel assemblies and gas blocks? I'm a newbie, bear with me here...

I am putting together a carbine that will have a EOTech holosight on it, so I want flip-up front and hind sights. I was thinking of getting the Superlight 16" barrel, but is it even possible for them to put a machined gas block on there that will accomodate the BMAS flip-up front sight? I also thought of using a tri-rail gas block, but I don't really need the rail space (already have quad rail hand guards for the rifle). Plus, maybe the that tri rail gas block is too large for the barrel?
Might I need to go with the 16" heavy dissapator so I can get a gas block that will accomodate the flip up front sight? Is the 16" dissapator even threaded for flash hiders/compensators? (It doesn't really describe the barrel well on their website).

Thanks.

Your options for the superlight are basically limited to the PRI front flip sight with the 0.625" gas block diameter.  You can also get a 0.626" front flip sight from GG&G, but that setup requires taper pin installation, which isn't your average DIY project.  Both of these are ~$200 options, the GG&G being more probably with the 'smithing fees required for installation.

OR

Stick with your standard FSB on the superlight.

If you step up to the Dissy barrel, more FSB options open up to you, but the forward FSB on a Dissy barrel is a nonfunctioning sight.  Once again, your options are limited to clamp on style sights again, like the PRI.  It can and has been done.  The issue is that the barrel forward of the shaved, functional gas block is around 0.720" and most standard gas blocks are 0.750", thus the need for a clamp on that can squeeze down to make up the difference.

I have no experience with holosights (except on pistols). I am concerned that the standard font sight would get in the way and be bothersome while trying to use the EOTech.

Thank you for your reply.

Any other ideas are welcome as well (barrels from other companies that would work on my existing Bushmaster upper, etc...).

I have also emailed Bushmaster to see what smithing they can do for me. At this point, I have no tools for milling, etc.

You could buy a LaRue Eotech mount and that will put the front sight in the bottom third of your eotech window.