I need a spare complete AR15 lower and am considering Armalite, Bushmaster, Rock River or a new production Colt.  I was told buy a Colt rep that their current production lowers have MILSPEC take down pins and no longer have the annoying sear block installed.

Can some one conform this?

Also, do current production Colt lowers have MILSPEC size trigger and hammer pin holes?

The lower must function with a complete M16 upper with M16 bolt carrier as well as accept standard MILSPEC size trigger and hammer pins as I already have $$$ invested in KAC triggers with standard pins.  I must also have absolutely interchangability between any M16 upper so a really tight lower that may require fitting is not what I am looking for.

Thanks,
Darrow

It is illegal to put a M16 upper or any M16 parts on any nonregistered lower.

I'm in the military and this is for my official duties.  

Darrow

Number 1)  There is NO MILSPEC for an AR-15!  The MILSPEC is for an M-16.

Number 2)  If you are truly needing this for official duties, go ask your unit's armorer, if he/she is halfway competent, they'll know or be able to find out for you.

No disrespect ment if its an honest question, but it smells of [:K]
FOTBR

I have never heard that M-16 uppers were illegal.  Hell who can tell the difference.  As long as the upper doesn't have the M-16 bolt carrier in it there should be no problem.  Also the 16 inch barrel length also must be maintained.



Bobwrench

Yes, they've got a milspec 1/4" pivot pin now - the takedown pins have always been 1/4".
There is no longer a separate sear block installed, but colt leaves the place where it would have gone totally unmachined, so there's still a big unmachined web of aluminum in the colt receivers preventing installation of a sear.



Nope, they went bigger - .170 instead of roughly .156.



Then just about anything BUT a colt will work.  The colt will work if you don't mind oversized hammer and trigger pins.

To: FanoftheBlackRifle

In reading my post now I agree it looks a little suspicious.  

With respect to your first statement I realize there is no MILSPEC for the AR15 however, I was only asking if individual features of different manufactures conformed to the MISLPEC.

As for your second statement, I was recently selected as a member of the All Army Reserve Service Rifle Team.  The Team members are spread out all over the country so theres not unit armorer I have easy access to.  We are issued two complete AMU prepared M16 uppers because storage and security requirements make it difficult to issue complete M16 rifles  therfore we are required to provide our own AR15 lowers.

Darrow

Even if the person owns a registered Drop In Auto Sear?

I know new Colt lowers have the small (standard) takedown pin and don't have the block, but the hammer and trigger pins are still the PC oversize.

Darrow,
[:D]  OK, I probably overreacted a little, but I tried to keep it in check; most of the time when someone starts asking about anything M16 related shortly after they begin posting, it goes rapidly downhill from there.

I knew what you ment about the milspec question, but its just one of those things that bug me [:D]

Congratulations on making the service rifle team.

I have a Bushmaster, and love the thing; as far as I know, all the pieces are interchangeable with corresponding parts from M16s, however it wouldn't be legal for me to try (all of the parts), nor do I have any desire to mess with a damned near perfect product.

FOTBR

I purchased a CLE rifle with Krieger barrel through the CMP and have had no problems with the Bushmaster lower other than the POS trigger.  Dropped in a new KAC a couple months ago and quickly solved that problem.  I'll probably go with another complete assembled lower from Bushmaster or Armalite.  That way if I have any serious problems I can just send the whole thing back and use my back up lower until it's repaired.

Darrow

Since you're not putting in any M16 trigger/sear/hammer parts anything should work.  Anything but Colt will have standard pins.  You might want to get one of the RRA lowers with their 2-stage trigger in it.  It'll be a better trigger than the stock one the BM comes with for sure, and the highpower guys speak highly of them.

Darrow, it sounds to me like you want a lower receiver that is MIL-SPEC [b]except it lacks a autosear hole[/b].

Thus, you can use all the AR15 [b]and[/b] M16 parts in it, except the autosear in a select-fire kit will have nowhere to go so you'd toss it in your drawer.

A Colt receiver is [b]not[/b] what you want. A current-production receiver that I'm sure fits my above description will be a Bushmaster. (color issues aside which i'm not clear about)

I sure hope there are other big manufacturers who are making no-bullshit lowers like BM, but I'm not familiar with other makers. Other boardmembers will chime in about RRA/armalite/oly/etc.