Is it legal to use an M16 bolt carrier if all of the other internal parts are AR15 parts?

Only if you want to go to jail!

It is illegal. It is also likly that no one would ever know. However it is best to be on the safe side as getting locked up and having to pay a lawyer to TRY and keep you out of jail just is not worth it. It is best to spend the extra couple of bucks for the new bolt carrier.

Not according to ATF in their "Rules-Regulations book--ATF Publication 5300.4

I would not advise it- don't do it.  But, it is NOT illegal so long as, together with your other semi-auto components, your AR does not fire FA.

See this [URL]ar15.com/forums/topic.html?id=104568[/URL]

Thanks for your help!

It's real simple.  The law states that you are in trouble if a part, or combination of parts, enables FA.  Under your hypo, you'd be in trouble.  HOWEVER, an M16 bolt assmbly alone will not enable FA and therefore is not prohibited by federal law.  

As always, my advice is don't do it since there's no point.  

Right, that makes sense and is consistent with what I've said all along.  If, without the "correct hammer and trigger" and/or by removing or "manipulating" the disconnecter you get FA (which includes a double fire), then you are in violation of the code section.

Otherwise, you are not.  Meaning, if you don't mess with the disconnector (or remove it) and have the other semi-auto parts, you are OK with just the bolt carrier in your upper.  

Again, don't do it.

BTW, ATF's admonition that you should not have an M16 bolt carrier in your rifle is akin to my constant admonitions not to do it.  However, you are confusing this admonition with a RULE or some recitation of existing law.  That is an incorrect position.  If you want to say that it is advisable not to do it (as I do) then fine, but if you proffer that it is the law then you are wrong.  It's not.  You have simply picked out "bolt carrier" from the above text and proffered, out of context, that it alone in an upper is illegal.  That is not accurate.

It is accurate to say, as I have all along, that if the carrier IN COMBINATION WITH OTHER PARTS OR MANIPULATED PARTS ( like the disconnecter) creates FA, you are now breaking the law.  If not, then no law is broken (just my admonition).

What do you mean by "them"?  

Again, under your hypo, the carrier is used in combination with other non-AR parts (or lack thereof) to enable FA.  That's a problem under the code.  Without the other manipulated or removed part, there is no violation.

With all the confusion i would avoid it.From what i know is that any m16 part in a semi auto is illegal.

RIGHT.



WRONG.

I hate to keep beating a dead horse, but this is very simple.  "Any M16 part" in your AR is NOT per se a violation of the law.  I kinda wish it was so I could just agree with everyone (including the guys at Bushmaster).  However, the code section is clear; it does not take a lawyer to figure out its meaning.  If the part or parts allow for FA fire (including double fire), then the part/parts is/are considered an unregistered machinegun.  If the part, alone, in your AR, does NOT allow FA fire, then you have NOT violated the law.

YES, its that simple.  I hate to keep saying this over and over but I constantly see this misconception about what is otherwise a very unambiguous federal code section and it frustrates me.

I have no problem with people, like me, saying "DON'T DO IT, THERE'S NO POINT . . .", however, let's not confuse ourselves on what the law is.

Just curious,does the BATF have to show criminal intent also?

Actually, the ATF does not have the burden of "proving" anything; that's up to an Assistant U.S. Attorney who first screens the case for prosecution.

And the criminal intent component of the code section in question is the "knowing" possession of the part or parts needed to readily assemble an unregistered MG.  Again, not very complicated stuff.

Govern yourselves accordingly.