I am going to buy a new M4 Bushmaster soon.  I have been doing some reading on this site for the past 3-4 days, and I keep coming across horror stories about the Loudness, and loss of bullet velocity due to the Fixed Y comp that comes with the Gun.  Here is my question..
Is it worth the time/effort to have an M4 specially built with this Upper found at this link?  http://www.bushmaster.com/shopping/uppers/post-ban/pura2b16m4.asp
The Part is PURA2B 16M4.  I got this idea from another post, I don't remember that persons name sorry.
How loud is the gun?  Use a scale of 1-10, ten being the loudest gun you ever heard.
I hope I am not asking stupid questions, but I thought before I spend the cash I would bring my little dilemma before the Experts.  
Any help or suggestions Will be greatly appreciated.
Jlink

I haven't fired this gun, but I do have some experience with how loud it is.  I was at the range the other day with my Rock River Arms upper M4(fake Flash Hider that does nothing, basically a regular barrel with nothing on the end).  Halfway through my time there I was getting ready to shoot when someone opened up 7 bays down with me with something LOUD.  I put my rifle down and stepped back to note that it was an AR.  I figured someone had an AR that was for a different caliber.  Went down to take a look while this guy was reloading and found it was a bushmaster with the mini-y comp.  I woudn't say it was the loudest gun I've ever heard, but it was probably twice as loud as mine.
From reading other posts on the board, I would go with a different comp or none at all.
Good luck with your decision.

It is worth the time/effort to get the 16" M4 upper.

But better yet is the lightweight rifle [url]http://www.bushmaster.com/shopping/weapons/pcwa2x16sl.asp[/url] no annoying blast, its even lighter, and its just as accurate.

Or you can do what many of us do.  Buy a complete lower from your FFL - then order an upper 'custom built'.  You could order a flattop with the lightweight barrel for example.

I love my bushy m4 with the miny y comp,but it is very loud, on a scale of 1-10 I would rate it a 10 for loudness also a 10 for effectiveness,it is a love hate thing.

I'd purchased a bushy A2 shorty, than added Car stock and brake, all postban configuration.[:)]
[IMG]http://www.metrophotohost.com/gallery_0010/gallery_albums/TMO-Member-Favorite-Battle-Rifles/TGbushyM4.jpg[/IMG]

It has beed 100% dependable.

TG

Not to make things more difficult, if I were to build another carbine from ground up, i would seriously consider a mid length carbine.  Armalite and Rock river makes those and the advantage of lower impulse on the gas will definitely make a enhance carbine which is most likely the wave of the future.  for the past thirteen years I have been shooting a variation of the M4, I am going to a mid length for my next build.

I have the Bushmaster M-4 type A-2 rifle, and mine is in stock condition.

I have one suggestion if you are looking for an excellent AR-15 type rifle, 'buy it'.

And wear ear plugs in any configuration.

It is an excellent tactical rifle in every regard.

Thanks for all the replies.  I am having my M4 built with that Upper that I mentioned above.  
If anyone is interested in the part# of the whole gun is PCWA2X16M4.  That will build you an M4 Carbine w/o Y Comp that cause the loudness.
jlink