M4/M16/AR15 Bolt Carrier Question

[EdLaver]

I know this is a stupid question but I want to be sure...

Does it matter if you buy a full auto bolt as opposed to a semi auto bolt to be used in a semi auto ar15?

I am interested in buying a LMT bolt carrier assembly and I just want to make sure. I dont want to go to the range and get busted like that one guy did a while back .

If its ok, then what are the differences between the two and why would it be better to have the full auto over the semi auto bolt.

Thanks!

-Edlaver

 

[Rubber_Duck]

Yes, it is perfectly legal to have an M16 carrier in your AR-15, AS LONG AS THERE ARE NO OTHER M16 PARTS. I have an M16 bolt Carrier group in my Bushmaster as I type this.

So M16 bolt carrier OK, M16 fire control group parts NOT OK.

 

[ugaarguy]

If its ok, then what are the differences between the two and why would it be better to have the full auto over the semi auto bolt.

M16 bolts are heavier (more material on the bottom) which moderately slows the cyclic rate of the rifle. Some say this leads to lower felt recoil. Another big advantage is that slower cycling eases extraction, which is particularly important on short carbine length gas systems.

 

[ants]

Edlaver, this is one of those issues that gets argued forever down to the deepest bowels of the Internet archives. In fact, the controversy only exists on these Internet forums. All the various bolt carrier types are sold without control or regulation on the open market by respectable name-brand retailers because there is no legal issue involved at all.

But half the guys on the Internet will unceasingly argue one way, while the other half argues the other way. It will never end.

 

[Hoppy590]

no legal issues at all.

If its ok, then what are the differences between the two and why would it be better to have the full auto over the semi auto bolt.

the difference is the milling on the carrier. this stops SA carriers from working in FA guns,or rather stops conversions. as is my understanding . you need a m16 carrier to do FA. but the M16 carrier does not MAKE a gun FA. like, you need wheels to drive your car, but your wheels dont actually move the car, the engine does.

http://quarterbore.com/images/ar15_sp1_m16carriers_sm.jpg
the top is a SA commercial carrier, middle is Colt SP1, bottom is M16

theres no real benefit to a FA BCG in a SA gun.

 

[rob_s]

Actually, there are two benefits to an M16 carrier in a semi-auto gun.

The first is as mentioned above with regards to greater mass.

The second is the shrouded firing pin such that the carrier cocks the hammer and not the firing pin.