I have a Colt green label M4 but was looking to get another AR rifle- I know some quality parts producers are out there but few that are actual mil-spec. I know the old Eagle Lowers were mi-spec but as far as new parts being produced. Heard that Rock River, DPMS, and a few others were not mil-spec. Are my only choices Bushmaster or Colt?

Actually the Bushmasters and Colts are not 100% mil-spec either.  None of them are.  Let me list some examples:

Colt uses “oversized” fire control pins
RRA & Bushmaster use 1/9 twist in their barrels
Olympic & DPMS do not chrome line their barrels

We could go on and on here but the point is none of them make a true mil-spec civilian AR.  

Colt has some units in circulation with milspec fire control parts, no sear block, etc.

Bushmaster has 14.5" and 20" 1/7 twist milspec barrels.

DPMS has milspec 1/7 chrome lined barrels but the front sights are cast, not forged.

The only companies I know of with 4150 steel barrels are Bushmaster, Colt, DPMS.

There is no such thing as a "milspec AR15 lower" as none will have the sear hole.  Only Colt uses the correct extension tube on carbines.

However if you want an AR15 with aftermarket stock and folding front sight there are some viable combinations in there.

The only things you want to really check are:

Will it fit a RDIAS and any after market trigger I want?
Does it have a chrome lined, 1/7 twist, 4150 steel barrel?
Will the stock I want fit on the lower reciever extension or must I buy a new one?
Is my bolt/carrier as close to milspec as possible? (I suggest Bushmaster or Colt M16 units)
Are the 1913 rails on my upper to propper spec?

Its legal.  Use the search function to see that mess if you wanna see it but I dont wanna debate it again.  ATF refuses to acknowledge my orignal letter for clarification.  I will be sending another letter that is notarised and sent with signed delivery.

The ATF only cares if your rifle fires fully automatically.  They RECOMEND you dont have full auto parts so you dont accidentally end up with too many full auto parts to create a machinegun.

CDNN is currently selling  brand new Colt M16 takeoff bolt/carrier assemblies for $100. There are none better and the price is definitely as good as you're ever going to find [:D][url]www.cdnninvestments.com[/url]

DevL is absolutely correct in his legal point, but if you're paranoid about it, just do what I did years ago. Grind back that bottom edge of the carrier, that trips the auto sear, back about 3/8 inch. Takes about 10-15 minutes w/ a Dremel tool, if you work slow like me. Then you still have the weight and function advantages of the M16 carrier, without having to worry about who's right or wrong on this issue[:D]

Hey Paul,
Did you really mean to state the the assemblies are Colt "takeoff"s?

BTW, I am in Dallas.

Dave S