How is the front sight block installed? How do you establish top dead center alignment? I have not seen any pictures of barrels before the front site was installed and I have not yet sprung the $20 bucks needed for Bushmaster's installation video.

It is it easy to swap out front sites?

I am a little unclear, I will try to help:

Are you going from a standard sight to a gas block?

Is the barrel already drilled for the front sight housing? (typically barrels are supplied with the housing installed in alignment with the barrel index pin)


Robert
www.rbprecision.com

OK I probably have used two different parts names here. I am not new to AR's but I am to the idea of building one.

The standard A2 front site that would normally be found on a 16 or 20" barrel has the gas block included in the fron site housing correct?

The reason for my question:

I intend to acquire an entire A3 upper w/ 16" barrel. Eventually ( when the part becomes available for sale ) I want to replace the A2 front site with one of Les Baer's new flip up front sites that they are using on their new Thunder Ranch carbine. I also intend to use the same free float tube they use on this new carbine of theirs.

I will purchase the complete upper from Bushmaster. They told me they would install the replacement front sight and float tube at no charge as long as I purchase their upper. I like that idea.

The parts from Les Baer will not be available for a few months and I really do not want to wait that long to purchase the upper. I have the money now. If I wait something may come up and it will not be a good time to spend that much on myself. Yes I am married.

Will swapping out the existing A2 sight for Les Baer's flip up front site be a real hassle? The people at Bushmaster said it is compatible.

Buy the A3 upper now and figure out how to replace everything later or wait and have my custom carbine upper arrive ready to go?