semi vs full auto bolt carrier

[DrBaker]

Can anyone point me to some good pics that show the difference between an AR15 and an M16 bcg?

I assume the M16 bcg will work just fine in a semi AR, but what happens when you put a semi bcg in a M16?

[CAR-AR-M16]

http://www.ar15.com/content/legal/ar15-m16parts/boltCarrier.gif

If you put an AR carrier in an M16 (either a register receiver or one using a RDIAS) it will not fire full auto. If you are using a Lightning Link as the conversion device you need to use the AR carrier like the middle one pictured above.

[DrBaker]

Thanks for the pic. I just went to the safe to check things out.

I want to try my LMT sbr upper on a M16. WetWork got his M16 about a week ago and we pulled the bcg out of it and compared it to the one in my SBR. We couldn't find any differences. My SBR bcg looks just like the top one in your pic above. I guess they just sent me the "good" one when I ordered the upper.

[DrBaker]

One more question. Other than not working in full auto, will the AR carrier in the M16 damage anything?

[CAR-AR-M16]

One more question. Other than not working in full auto, will the AR carrier in the M16 damage anything?

I don't see how it could. In fact if you put an AR carrier in a registered receiver M16 and place the selector in full auto it will probably only fire one round and then the auto sear will just hold the hammer back preventing it from firing again. The longer enclosed portion on the bottom of the carrier is what trips the auto sear to release the hammer.

[Glocktogo]

I don't remember the details, but i have heard that if you have certain M-16 parts installed on a non-registered reciever gun, it is a violation of NFA law (even if the gun won't fire FA with the part installed). Don't quote me on this as I could be wrong, but you may want to check it out.

Jerry B.

[Stoverarms]

SEE DA LINK!

http://www.atf.gov/pub/fire-explo_pub/2005/p53004/gen_info.pdf

2. INFORMATION CONCERNING AR-15 TYPE RIFLES
ATF has encountered various AR-15 type assault rifles such as those manufactured by Colt, E.A. Company, SGW, Sendra and others, which have been assembled with fire control components designed for use in M16 achineguns. The vast majority of these rifles which have been assembled with an M16 bolt carrier, hammer, trigger, disconnector and selector will fire automatically merely by manipulation of the selector or removal of the disconnector. Many ofthese rifles using less than the 5 M16 parts listed above also will shoot automatically by manipulation of the selector or removal of the disconnector. Any weapon which shoots automatically more than 1 shot without manual reloading, by a single function of the trigger, is a machinegun as defined in 26 U.S.C. 5845(b), the National Firearms Act (NFA). The definition of a machinegun also includes any combination of parts from which a machinegun
may be assembled, if such parts are in possession or under the control of a person. An AR-15 type assault rifle which fires more than 1 shot by a single function of the trigger is a machinegun under the NFA. Any machinegun is
subject to the NFA and the possession of an unregistered machinegun could subject the possessor to criminal prosecution. Additionally, these rifles could pose a safety hazard in that they may fire automatically without the user being aware that the weapon will fire more than 1 shot with a single pull of the trigger. In order to avoid violations of the NFA, M16 hammers, triggers, disconnectors, selectors and bolt carriers must not be used in assembly of AR-15 type semiautomatic rifles, unless the M16 parts have been modified to AR-15 Model SP1 configuration. Any AR-15 type rifles which have been assembled with M16 internal components should have those parts removed and replaced with AR-15 Model SP1 type parts which are available commercially. The M16 omponents also may be modified to AR-15 Model SP1 configuration. It is important to note that any modification of the M16 parts should be attempted by fully qualified personnel only. Should you have any questions concerning
AR-15 type rifles with M16 parts, please contact your nearest ATF office. A list of ATF field offices is on page 198 of this publication.

[NavyLT]

So, reading the above it seems OK to put AR-15 parts into an M-16 receiver, you just can't do it the other way around.

[AKguy1985]

I've always wondered what are the differences in a AR-15 vs m-16?? i know the trigger group and bolt and bolt carrier, anything else different?

[CAR-AR-M16]

I've always wondered what are the differences in a AR-15 vs m-16?? i know the trigger group and bolt and bolt carrier, anything else different?

The trigger group (hammer, selector, disconnector and trigger) are different as well as the bolt carrier. The bolt itself is the same. The receiver is also milled out and drilled to accept the auto sear. There is some good info on the parts differences at the ar15.com website (http://www.ar15.com/content/legal/AR15-M16Parts/). Below is a picture from Quaterbore's website showing the internals in the receiver of an AR vs M16.

http://www.quarterbore.com/images/nfa-ar-m16-01.jpg

[ssgrock3]

good info

[NikatKimber]

what is the part circled in red?

http://img1.putfile.com/thumb/4/10818260365.jpg (http://www.putfile.com/pic.php?img=5264132)

[Stoverarms]

M-16 auto sear. No reason to own one unless you own a registered M16. As stated above don't mix/possess M16 parts an a AR15 if you do not own a registered M16.

[NavyLT]

Parts diagrams are here:

http://www.fulton-armory.com/M6Parts.htm

[sharpshooter]

There is a lot of good information concerning this on ARF.com, Including newer letters from the ATFE concerning this. Just using an M16 BCG in an AR is not a violation of the regs. Colt has been doing it in their rifles for quite sometime now. This is common knowledge. The big no no is to have the FCG parts. I will get the link to the latest information conerning this so you can read it for your selves.

[DrBaker]

There is a lot of good information concerning this on ARF.com, Including newer letters from the ATFE concerning this. Just using an M16 BCG in an AR is not a violation of the regs. Colt has been doing it in their rifles for quite sometime now. This is common knowledge. The big no no is to have the FCG parts. I will get the link to the latest information conerning this so you can read it for your selves.

I read that somewhere too. I guess some of the manufacturers were using the bolt carrier in the normal production.

[sharpshooter]

Colt got permission from ATFE to use M16BCG in their sporter rifles, it was mainly a move to cut down on thier manufacturing costs (not having to produce two seperate parts that do the same thing).

I read that somewhere too. I guess some of the manufacturers were using the bolt carrier in the normal production.

[CAR-AR-M16]

Below is the text of the letter that ATFE sent to Colt. Read it and draw your own conclusions:

U.S. Department of Justice

Bureau of Alcohol, Tobacco
Firearms and Explosives

903050:RV
3311/2005-167
www.atf.gov

Legal Department

Mr. Carlton S. Chen
Colt Defense LLC
547 New Park Avenue
West Hartford, CT 06110

Dear Mr. Chen:

This is in reference to your most recent facsimile transmitted to the Firearms Technology Branch (FTB), Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), on January 13, 2005. In your faxed letter, you seek clarification regarding the use of M16 machinegun bolt carriers in AR-15 type weapons.

As you are aware, since your provision of copies of relevant material in your previous faxes, ATF has previously addressed the use of M16 machinegun fire-control components in AR-15 type rifles in the General Information section of the Federal Firearms Regulations Reference Guide (ATF P 5300.4). (Please refer to page 115, item #3, “Important Information Concerning AR-15 Type Rifles.”)

However, we would like to direct your attention to a particular paragraph of item #3, which states the following:

In order to avoid violations of the NFA, M16 hammers, triggers, disconnectors, selectors and bolt carriers must not be used in assembly of AR-15 type semiautomatic rifles, unless the M16 parts have been modified to AR-15 Model SP1 configuration. Any AR-15 type rifles which have been assembled with M16 internal components should have those parts removed and replaced with AR-15 Model SP1 type parts which are available commercially. The M16 components also may be modified to AR-15 Model SP1 configuration.

Accordingly, based on previous FTB recommendations not to install this bolt carrier and the conclusions presented in the passage cited above, our Branch cannot specifically authorize you to install an M16 bolt carrier into an AR15 rifle. Also, we cannot definitively tell you that installing an M16 bolt carrier in an AR 15 will make that firearm fire automatically.

We can only inform you that if this installation were to create a firearm that fires automatically, it would be a machinegun as defined; conversely, if it did not result in the production of a weapon that shoots automatically, it would be lawful to posses and make.

We thank you for your inquiry and trust the foregoing has been responsive.

Sincerely yours,

[signed]

Sterling Nixon
Chief, Firearms Technology Branch