I currently have a Bushmaster 20" A3 which I have enjoyed shooting, but its pretty heavy. I currently have a Trijicon Reflex mounted to the flat top with a B-Square riser to put the dot above the front sight. I think what I would like to do is scope the 20" upper, and pick up a LIGHTWEIGHT upper and use my reflex on that.

I have decided to stay with Bushmaster after reading a little bit.

All I am going to be using this upper for is close up, fast shooting with my reflex. Anyone care to stick me in the right direction. I dont really need any iron sights if I continue with the reflex, so flat top would be prefered. I guess if the AWB sunsets I would like the ability to add a flash hider, I guess that can be done to any barrel?

I think the boards favorite is my own favorite as well when it comes to a carbine is the M4 flattop....

The Bushmaster M4A3 upper is a solid choice and I would go with the flattop and the full front sight.  Given that you have a post-ban, I would go with a 14.5-inch barrel with the Mini Y Comp.  With that said, there are MANY great breaks available!!!

"Pete in NH" has been selling some very cool looking RRA barrels that have a pressed on flash supressor over a post-ban barrel.  These are quite possibly the BEST LOOKING of any post ban barrel I have seen and would be my choice but it would not be a Bushmaster barrel!

As far as threading a barrel after the AW ban sunset...  I would buy what you like in a post-ban configuration and if the ban does sunset, you can hate me for my poor advise later!  I don't think the ban will go away and I wouldn't buy planning to thread a barrel later!  If the ban dies, just buy a new threaded barrel!

Here is the link to Pete's barrels...

[url]http://www.ar15.com/forums/topic.html?b=7&f=22&t=132989[/url]

[img]http://image1ex.villagephotos.com/pubimage.asp?id_=193258[/img]

Next Question.....Do I need to buy a new charging handle and bolt carrier or are the ones from my current Bushy usable. I read somewhere that your not supposed to swap carriers between uppers for some reason, but that didnt make much sense to me.

Thanks

I just got my order in from Bushmaster. I got the 16inch govt. profile and A2 upper. Amazingly light. I am planning to mate this with a PWA preban forged lower, and an A1 (or M16, can't decide) stock. I am putting this together for next summers trip to Thunder Ranch. (brag on) I'm going to take pistol and carbine H.I.T. classes back to back, six days of blasting (brag off). Even though my M4(gery) is light I think this new darling might be the ticket for the "urban carbine" concept.

The problem: if your going postban the 16inch govt. profile has a threaded barrel. I guess you would have to (ugh) permanently attach something to the end of it per BATF regulations.

The reason you don't make a habit of swapping bolt carrier assemblies from weapon to weapon (or, more appropriately, upper to upper) is due to headspace.  An improperly headspaced AR can cause mega-problems, up to & including a KB.  I've yet to have one fail a gauge test, but am careful nonetheless.  (Plan on buying a good set of headspace gauges for your AR tool bag.)  Ideally, you should have a dedicated bolt carrier for each upper.  
I'd also vote for a Bushy 16" M4A3, just send it to Kurt for the installation of one of his fine brakes.

I like to keep a dedicated bolt/carrier/charging handle with my uppers but in general they are interchangable as Bushmaster sure as heck doesn't custom fit every bolt to every barrel!

Where this becomes a potential problem is when you have a special barrel built for a special use (AS MY DCM UPPER) where the barrel was custom fitted to a specific bolt!  I would never want to use just ANY bolt with this barrel even though the bolt I had used to fit the barrel to was a standard Colt Bolt from my Match HBAR!  Now any bolt MAY work just fine but I KNOW the one that the barrel was fitted for will provide a tight fit!  It doesn't sound to me like this is a concern you need to worry about!

Good Luck!

bushy also makes a 16" dissipator that is the lightweight profile under the handguards, and postban as well.

[url]http://bushmaster.com/shopping/barrel-assemblies/pbbl-16dm4a.asp[/url]

Posted by Quarterbore:

[b]"Pete in NH" has been selling some very cool looking RRA barrels that have a pressed on flash supressor over a post-ban barrel. These are quite possibly the BEST LOOKING of any post ban barrel I have seen and would be my choice but it would not be a Bushmaster barrel![/b]

I can't agree more!  I've owned two of them so far, one chromelined and one chrome moly, and both are VERY accurate and EXTREMELY well machined.  They are the sharpest looking barrels I've been able to find.

I'll jump on the bandwagon too.  I have two 16" uppers - one Bushy HBAR fluted (looks cool, stiff but light) one 16" M4gery with fake flash hider (looks cooler, lighter).  Both are quick handling and a lot of fun to shoot with an Aimpoint Comp M.  I like Pete's above.  

I've read a couple of articles that give the 16" barrels a significant edge over the 14.5" because of the higher muzzle velocity they produce.  That gives you a greater fragmentation range with any of the preferred military rounds and therefore a greater effective range.  Since the barrel has to be 16" anyway, why not make it all work in your favor.  Besides shooting next to somebody using a mini comp is a real pain.

Next answer.  I interchange my Bushy bolts and carrier to save money, but its a pain.  I'll probably order a second set this month.  

The faux flash supressor on Pete's barrel looks just like the Fulton Armory thing called "the look". Wonder if there's any difference?