Full Auto BCG? > AR Basics

Posted: 6/19/2016 8:25:55 PM EDT

PSA has full auto bolt carrier groups. What's the difference? I assume it is legal to put these in a standard semi rifle?

Posted: 6/19/2016 8:30:35 PM EDT

[#1]

Slightly heavier and perfectly legal.

Posted: 6/19/2016 9:07:24 PM EDT

[#2]

Not an issue; no difference in function in an AR-15. The full-auto bcg works with the auto-sear to reset and release the trigger. You don't have the full-auto fun parts so there's nothing to worry about.

Posted: 6/19/2016 9:27:36 PM EDT

[#3]

The bottom BCG is the full auto type, the area being pointed to interfaces with the auto sear.

The top one is a semi auto unit.

Posted: 6/20/2016 3:20:02 AM EDT

[#4]

Thank you all very much.

Posted: 6/20/2016 11:10:13 AM EDT

[#5]

Quoted:
PSA has full auto bolt carrier groups. What's the difference? I assume it is legal to put these in a standard semi rifle?

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"Full-auto" bolt carrier is a bit of a misnomer.

Installing one of these in your AR will not make it somehow a machine gun, and if one were to illegally make an AR a machine gun, they don't have to use one...

Posted: 6/20/2016 11:54:23 AM EDT

[#6]

I have read they are a little better balanced because of the more equal material top and bottom... not sure how big of a deal that is.

My first rifle has one and as soon as AIM decides to ship it my second one will too.

Posted: 6/20/2016 9:09:40 PM EDT

[#7]

Depending on exactly who made the "semi" and "full auto" carriers, the weight difference is very small. Some people feel the slightly heavier carrier helps smooth the cycling of their ARs, others can't tell the difference.

I like the "uncut" (full-auto profile) carrier for a number of reasons. One is that it's easier for me to fat-finger into the upper. Another is that when you call it a "full auto carrier" it makes some people irate to even hear that phrase.

Posted: 6/20/2016 11:15:27 PM EDT

[#8]

Quoted:
PSA has full auto bolt carrier groups. What's the difference? I assume it is legal to put these in a standard semi rifle?

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I own 11 of them that I purchased from PSA, they work just like the semi groups, just make sure and don't drill that third hole and you will be fine!

Posted: 6/27/2016 7:38:15 PM EDT

[#9]

As shown in the picture posted, the difference is a little extra metal on the bottom. That is used to trip the auto sear in an M16 assault rifle. In an AR15, it doesn't make a functional difference which carrier you have.

Funny enough today, I had both of my ARs at the range and tried the carriers back to back in both rifles to feel for a difference. The FA carrier might have felt a tiny bit smoother in the 16" carbine gas system. (certainly not enough to justify the cost of replacing a good bolt carrier) On the 18" rifle gas, there was no difference using the same ammo and firing from the bench.

As far as legality, your assumption is correct. The auto carrier is just fine in an AR15. When things get illegal is when you have M16 fire control group components (hammer, disconnector, sear, etc.) I'm not sure on the legality of possession of those parts, but I'd recommend keeping them out of your house. The BATFE tends to be rather... imaginative on some of the interpretations of their own rules.

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