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Discussion Starter · #1 ·
Not able to find any BCGs anywhere (online or in person) for months, i discovered today that Quantico Tactical in Lakewood, WA had one left in stock: a chrome RRA BCG for $160. Not really what I wanted (which was a basic MILSPEC phosphate LMT or BCM or DD), but I took it. RRAs have semi/AR15 carriers, not auto/M16 carriers. The QT guys swore that auto BCGs are illegal in Washington state. Really???? Since when???? Why are Colts still sold with auto BCGs if they're illegal? Something is fishy here. Thoughts?
 

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full auto bcgs are not illegal. whomever you talked to doesnt know much about ar15
 

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Or trying to sell you a semi auto bcg.

I have a RRA chrome bcg, its been exemplary over the years and a couple thousand rounds.

It is much easier to clean and does look nice.

You done good for $160.
 

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Being a Washington resident, I understand your confusion...while full auto firearms ARE illegal in WA State, the full auto bolt carrier group is NOT what determines if an AR is Full or Semi Auto.

That mechanical distinction is found in the trigger group, not the bolt carrier group. Dropping a full auto bolt carrier into a semi only AR will not make it a full auto rifle.

Hope that clears it up.

Tack
 

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Tack,
This is prhaps a dumb question, but wouldn't a full auto trigger group make any AR 'full' auto?

What's the point of a full auto BCG, Is it just tougher/higher quality?
 

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Tack,
This is prhaps a dumb question, but wouldn't a full auto trigger group make any AR 'full' auto?

What's the point of a full auto BCG, Is it just tougher/higher quality?
Yes...an auto trigger group would make it full auto and very illegal without the right paperwork.

Honestly, I don't know the exact difference between semi and full auto BCG's?

There is a visible difference in the carrier area where the hammer swings up and contacts the firing pin but that's the extent of my knowledge.

Perhaps on of out "builders" will be along shortly to clarify.


Tack
 

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The main difference is FA carriers are heavier. By increasing the mass, it slows down the time it takes to cycle thus helping FA become more manageable and reliable.

There is a little shroud too that protects the firing pin as it cycles. The bolt itself is exactly the same, only the carrier is different.

Other than that, not much difference in a semi auto AR. You can used either a FA or SA in a semi, but should only use a FA carrier in a FA/select fire weapon.
 

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The main thing about a FA carrier is that you're likely getting a BCG that is done right in all the areas that matter. With a SA carrier that's less likely.

Things that matter in a BCG for a true duty AR:

BCM Bolt Carrier Group (MPI) - Auto
Features
•Milspec Carpenter No. 158® steel
•HPT Bolt (High Pressure Tested/ Proof)
•MPI Bolt (Magnetic Particle Inspected)
•Shot Peened Bolt
•Chrome Lined Carrier (AUTO)
•Chrome Lined Gas Key
•Gas Key Hardened to USGI Specifications
•Grade 8 Hardened Fasteners
•Key Staked Per Mil-Spec
•Tool Steel Extractor
•BCM Extractor Spring
•Black Extractor Insert
•Mil-Spec Crane O-Ring
 

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Discussion Starter · #9 ·
Thanks, guys. I mentioned to the gun shop guys what Tack explained (I.e. a full auto BCG in a semi rifle still only leaves you with a semi rifle), and I brought up the ATF letter which specifically permits this configuration), but he said the more restrictive WA law ("RCW" something or other) trumps the more lenient federal provision. I'm still puzzled by it. Now I need a stripped lower, which is a whole new nightmare to deal with. I saw a bunch of lowers at Rainier Arms last Friday when all hell broke loose. Now everybody's out of those too. I guess I should have bought a complete rifle a couple months ago when I first started planning my AR build. Oh well. Rainier is in pretty tight with Mega Arms out of Tumwater, WA, so hopefully they get more in before too long. Thanks again.
 

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The main difference is FA carriers are heavier. By increasing the mass, it slows down the time it takes to cycle thus helping FA become more manageable and reliable.

There is a little shroud too that protects the firing pin as it cycles. The bolt itself is exactly the same, only the carrier is different.

Other than that, not much difference in a semi auto AR. You can used either a FA or SA in a semi, but should only use a FA carrier in a FA/select fire weapon.
I thought there was a timing issue too, something about the difference on the bottom of the carrier that changed the timing of when the auto sear was engaged? or is that added metal simply there for mass?
 

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I believe that is the shroud I am refering to. IIRC it prevents the hammer from hitting the firing pin as the bcg cycles out of battery. I'm not sure what it does on a FA fire control group tho, as I do not fully understand how they work.
 

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Knowing too much could be too tempting to some. Maybe legally it's better not to fully understand how they work! :D

For me, and most of us, it's not that tempting. A full auto firearm is the last thing I need but I do want the higher quality bolt and carrier since it's such an important component of the AR. Looking at diagrams of the full auto and burst trigger group it's pretty confusing to me. And it was 1968 since I last held an M16!
 

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I thought there was a timing issue too, something about the difference on the bottom of the carrier that changed the timing of when the auto sear was engaged? or is that added metal simply there for mass?
The timing issue has to do with the weight. The heavier it is the slower it cylces.

Heavier doesn't necessarily mean better.

The race gun guys like to run lightweight BCGs and Buffers so they can cut down on split times.
 

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Knowing too much could be too tempting to some. Maybe legally it's better not to fully understand how they work! :D
Amen to that. :rolleyes:
 

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Ran across a picture and thought of you....



Here ya go, enjoy.


top, semi auto.

middle, enhanced.

Botton full auto, notice how much less exposed the firing pin is.
 

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Most SA BCGs today are enchanced. The top one is really only found on older 30+ year old ARs
 
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