Question about AR15 being made full auto

JRW (QOR)

JRW (QOR)

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Im in a bit of a debate in a Yahoo forum on gun control. Someone in the States said an AR15 can be made full auto simply by using an M4 lower. Is that true? Somehow I dont think it would work.
 
While I'm no expert... It sounds plausible. Since it's a whole different gun. That's not really making a previous semi into a full auto, it's more like swapping uppers on a already full auto. To my unbelievably limited knowledge.
 
Full auto requires a full auto BCG (Bolt Carrier Group) and a full auto FCG (Fire Control Group).

If you were to use a SA BCG combined with a FA FCG, it would only function as SA.

If you were to use a FA BCG with a SA FCG, it would only function as a SA.

So.... Yes and no.
 
The lower is the gun. So they are correct. You can make a semi-auto AR-15 into a full automatic if you replace it with a fully automatic gun. Which of course is a rather silly statement.


It is the lower that we register as 'the gun', uppers, barrels, etc can be changed. But the lower represents the portion of the gun with the serial number.

Full Auto lowers have been prohibited for sale to the general public in Canada since 1977 and in the USA since 1986.

Kirk
 
kirkf said:
The lower is the gun. So they are correct. You can make a semi-auto AR-15 into a full automatic if you replace it with a fully automatic gun. Which of course is a rather silly statement.


It is the lower that we register as 'the gun', uppers, barrels, etc can be changed. But the lower represents the portion of the gun with the serial number.

Full Auto lowers have been prohibited for sale to the general public in Canada since 1977 and in the USA since 1986.

Kirk
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Agreed, LOL!
 
So I can make my VW into a Ferrari just by swapping out the power train and chassis and tires. Since I can still use the VW emblem on the hood I can make a VW into a Ferrari.
 
Yup, as long as the upper has a F/A bolt carrier then it will go fast when you attach it to a F/A lower.

So I can make my VW into a Ferrari just by swapping out the power train and chassis and tires. Since I can still use the VW emblem on the hood I can make a VW into a Ferrari.
Click to expand...

It won't be a 'real' Ferrari, but it sure will haul ass. Kind of a silly comparison.
 
You can take a SA lower and turn it into FA. All you need to do is mill out some material from the inside of the lower, drill the hole for the FA sear, change out the trigger sear, hammer and safety lever.

The commercial SA bolt will function in a FA gun and it will still be FA, just not for long. The FA bolt body is built to take the abuse, the commercial carrier will fail in FA mode.......

So in essence the VW = Ferrari analogy is correct!

Cheers!
 
My understanding was that the only difference between an FA and SA carrier was the FA carrier had extra material added to it to slow down the time it takes to cycle and therefore improve weapon control and reliability when firing in full auto.
 
notsorichguy said:
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The commercial SA bolt will function in a FA gun and it will still be FA, just not for long. The FA bolt body is built to take the abuse, the commercial carrier will fail in FA mode.......

snip
Cheers!
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No true at all. The extra metal on the bottom of the bolt carrier is what trips the full auto sear. Without a full auto bolt carrier, it will NOT operate as a full auto, even if you do have a full auto lower.
 
Ar180shooter said:
My understanding was that the only difference between an FA and SA carrier was the FA carrier had extra material added to it to slow down the time it takes to cycle and therefore improve weapon control and reliability when firing in full auto.
Click to expand...

That was my understanding and assumption as well.
 
The difference between an M16 and commercial bolt carrier is that the former has a ledge on the underside that is capable of tripping the auto sear. M16 carriers are actually commonplace nowadays on better quality AR-15 type rifles, as the extra mass is considered beneficial from a reliability and durability standpoint.

ar15carriers.jpg


A select fire lower with an upper containing an AR-15 bolt carrier will not produce automatic fire, as there is nothing to trip the auto sear. A lower without auto sear and select fire FCG parts may or may not function in automatic fire, as the hammer will follow the bolt carrier forward and may or may not strike the firing pin with enough force to ignite the primer.
 
JRW (QOR) said:
Im in a bit of a debate in a Yahoo forum on gun control. Someone in the States said an AR15 can be made full auto simply by using an M4 lower. Is that true? Somehow I dont think it would work.
Click to expand...

Yes, if it is a true, military specification full auto lower. However there were some colt Bcgs with the "full auto bridge" removed from them, I can't say for sure if that prevents FA fire or not. The thing is though that in Canada the lower is the firearm and you would require a seperate licence or a cadpat uniform to have access to one, i am not even going to try to understand what the laws are down south.
 
In the States a slidefire will get you pretty close.
I've heard it causally mentioned in the typical inaccurate, so somewhat hard to comprehend manor by the anti gun leaning talking heads.
 
Ar180shooter said:
My understanding was that the only difference between an FA and SA carrier was the FA carrier had extra material added to it to slow down the time it takes to cycle and therefore improve weapon control and reliability when firing in full auto.
Click to expand...

The fire control group has to be changed. If it was just that easy to make Ar15 into full auto, it would be prohibited like the SCAR.
Many of the retail stores will put on their website saying that FA carrier will not allow you fire your AR15 in full auto.
 
tjhaile said:
The difference between an M16 and commercial bolt carrier is that the former has a ledge on the underside that is capable of tripping the auto sear. M16 carriers are actually commonplace nowadays on better quality AR-15 type rifles, as the extra mass is considered beneficial from a reliability and durability standpoint.

ar15carriers.jpg


A select fire lower with an upper containing an AR-15 bolt carrier will not produce automatic fire, as there is nothing to trip the auto sear. A lower without auto sear and select fire FCG parts may or may not function in automatic fire, as the hammer will follow the bolt carrier forward and may or may not strike the firing pin with enough force to ignite the primer.
Click to expand...

That's what I thought but wasnt sure.

Thanks everyone, will pass this on as an urban myth.

I guess the fact is none have been seen on the streets, or it would be in the news big time.
 
Probably been covered but to put it simply... If you put an M4 lower on it to make it full auto it wouldn't be an AR15 it would be an M4.
 
So here's the real question. Does it make any difference? FA is far more effort to control than carefully placed semi auto fire. The belief that FA is more effective as a "spray and prey" or "mass killing" tool is pure BS. Regardless of operating mode, without a skilled user, its just a tool. One could argue that in FA the scumbag in question would be out of ammo sooner thus making themselves vulnerable to counter attack.

Here's a couple videos displaying some rather adequate semi auto fire.

http://www.youtube.com/watch?v=p4GQ6kugJ3M

http://www.youtube.com/watch?v=FaCpOt9xVy4&list=UUs5iRZoqlgf2YPtvjHfDdXw&index=31

http://www.youtube.com/watch?v=SVGPEgRZwIw&list=UUs5iRZoqlgf2YPtvjHfDdXw&index=32

Really, is FA needed????

TDC
 
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