I see lots of LMT Complete M4 uppers sold through various sites. I was wondering if the bolt carrier group in these things were legal to use with a AR.  

Are the LMT M4 bolt carrier groups any different from that of a AR?

(Simply) Can I slap the LMT M4 upper on my AR lower with out violating any Federal laws?

These are dumb questions, I just dont want to break any laws,
Thanks

14.5" LMT Uppers for registered SBR's I Believe...
14.5" LMT Uppers, have a gunsmith permanently  install a Phantom or Vortex then you can use this upper on your lower (16"). I'm no expert, I know more will chime in..

The one I was looking at had a 16in  barrel. I should have specified barrel length. Sorry.  But it was the bolt carrier I was asking about.

I have seen different photo's and descriptions of the bolt carrier that is in a M-16 and M4, and it is slightly different than my AR bolt carrier. So I can immediatly assume that there is a Full-Auto carrier group and another one for semi. Right?  Do the LMT M4s have the FA bolt carrier or a SA?
Is the LMT M4 bolt carrier considered a Class III or FA firearm component?


Thanks.

Thanks,

Quoted: Is the LMT M4 bolt carrier considered a Class III or FA firearm component?

No.

An M16 carrier is legal to use in your AR, and many do so for the added weight.  There is no difference in the bolts (excluding the LMT enhanced).

There is a ten page thread on this subject here.  In summary, it is legal to use an M16 (full auto) bolt carrier in your AR, but some recommend against it because of possible overzealous law enforcement.  IMHO, any LE who knows the difference between an auto carrier and a semi will realize that an auto carrier alone does not constitute a machine gun.

I also wrote to the ATF and told them I ran the M16 carrier with no issues and local LEOs have seen it too.  In short noone cares because its not illegal.

Does the LMT M16 carrier have the shrouded firing pin area? Anyone got a pic?

I was thinking about getting a complete BCG, or a LMT carrier+Colt Bolt.....

The LMT bolt & carrier groups are top notch. They come with a thick park on them that feals. A bit gritty at first. however the contact areas ware smooth with only a few mags through it. If you wanted you could knock the park off with a wire brush.  Go with the F/A group as all S/A carriers are too thin in the firing pin area.

After only 60 rounds through my Colt the area where the hammer rides the firing pin is wareing thin.

Quoted: Does the LMT M16 carrier have the shrouded firing pin area? Anyone got a pic? I was thinking about getting a complete BCG, or a LMT carrier+Colt Bolt.....

I've got the standard LMT bolt/carrier, It is shrouded around the firing pin, and it is circular at the end, but it isn't long enough to trip a sear......I'd post a pic, but my camera is in the shop for repairs....

've got the standard LMT bolt/carrier, It is shrouded around the firing pin, and it is circular at the end, but it isn't long enough to trip a sear

Basically like the current RRA carriers then?

I run auto carriers in everything. Someday I'll put them on someones RR and have ssome fun.

Quoted: 've got the standard LMT bolt/carrier, It is shrouded around the firing pin, and it is circular at the end, but it isn't long enough to trip a sear Basically like the current RRA carriers then?

I believe so,

There is a letter!!!!!!(Sort of)
I saw it on a BATF FAQ site a while back.  Someone asked if an M16 carrier could be used in an AR15 lower with the infamous Colt sear block (I realize the block would have to be ground down slightly for the M16 carrier to work) They said it was OK since there was no way to install the auto sear.  I don't remember them adressing the M16 carrier issue in an UNBLOCKED lower which seems to be the crux of this discussion.  I concur with the observation that AR15's probably never came with M16 carriers.  My 1964 SP1 serial #6xx has a carrier with a very slight cut out on the bottom front of the carrier.  My opinion always has been that if it doesn't shoot more than one shot with each pull of the trigger than it is NOT a machine gun.

An AR15 receiver even without the sear block requires extensive machining for auto use.