I want to build an AR-15h?

I would like to build it completely, but not sure if I want to go through the headspacing and making sure I line up the sights correctly.  Plus, I don't have the vice and other tools necessary to  for piecing together the entire upper assembly.  At least not for now.  I plan on building more guns in the future and will buy tools as time goes on.  

My friend also recommended that I go with a Colt bolt carrier assemly.  So, what company besides Bushmaster (comments on bushmaster uppers would be helpful too) sells complete uppers with flat-top receivers minus the bolt carrier assembly and charging handle?  I mean, is Bushmaster fine or is there something better?

I am going to use a titanium firing pin and DPMS lower receiver kit.  I'll go with a 6 position buttstock and I already have the lower receiver.  

Thoughts, comments would be helpful.  Thanks.

Why not post a build question in the build forum?


The titanium coated FP is a horrible idea.

why such a bad idea?

They tend to be brittle, and there is no real gain over the standard firing pin.

okay

Quoted:  A friend of mine suggested that I go with an A4 upper.  How is this different from an A3 upper? .

From Forest; What is an A1, A2, A3 or A4?

same exact thread here