I have the ambi selector in hand from Bushmaster.  This is my first AR15.  Can I do this myself or do I need some help?

if you have to ask, son, you need some help.

it sounds like your inexperienced in gunsmithing so may be a fun project for you.

get good tools.  gunsmith quality screwdrivers.  brass punches and long allen wrenches.  

look at how the parts (selector, trigger, etc. fit together.  draw pictures of the parts and their relationships to one another.  pay close attention to the springs and how they are installed and located.  when you have sketches and the operation "set" in your mind you can take the fire control system apart.  

pull off the pistol grip.  
punch out the pins and pull out all the little parts.  

install the ambi selector.
put the trigger and hammer back in making sure the springs go in the same way the drawings show.
test dry fire to confirm the selector functions.

Thanks, 308.  Sounds like the rest of my gunsmithing....

http://www.bushmaster.com/faqs/upper-lowerfaqs.asp#6

Got 'er done, 308wood.  Thanks again for the help.

Quoted: www.bushmaster.com/faqs/upper-lowerfaqs.asp#6