I am a nib bushmaster ar15a3 with a 16inch barrel,also have an ak-74 type muzzle brake. What scope or other type of system do you recommend? Thanks singleside out

Welcome aboard Single.... You have a TON of options. Your flat top upper gives you even more. There is no one all purpose optic that does everything (TA31 is close though ). Tell us what sort of shooting you would like to do and you'll find there is a lot of people here hwo can help you find the optic that will meet your needs best.

Basically, what ranges would you like for your optic to excell at 0-200? 0-300? 0-500? 100-500? Would you like the optic to help you moreso at fast paced close quarter shooting, or longer range accuracy? Also, some of the best optics are big big money. So keep this in mind as well. For an excellent quality optic, you should probably expect to pay between $400 and $1000. Ouch!

We'll get you scoped with a little more info.

You can expect to pay $350 to me for my NIB Sightron tactical scope, 6-24x42AO, satin finish, sun shade, fine cross hair dot reticle, lifetime warranty...  Its a steal.  I was going to put it on a Savage target rifle and ended up buying a Remington VS that already had a Springfield .308 scope on it.

http://www.sightron.com/scopes_s2_tar.html