Can I register my ar15 lower receiver as SBR w/o 11.5"upper

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bunker168
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Can I register my ar15 lower receiver as SBR w/o 11.5"upper

Post by bunker168 »

I got an Adams Arms 16" tactical full rifle

Down the road I will SBR it with an AA 11.5" upper.

While waiting for my suppressor form 4 to go through can I also do form 4 (I hope that's the same form for SBR) on my AA lower receiver?

Is it true when I change the upper to 11.5 I should also change the buffer spring? Appreciate any recommendation from you guys who have done it to make it reliable.

Can I also use 6.8 upper? with the 5.56 lower?

5.56 Magazine still usable on 6.8?
dtom29
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by dtom29 »

Yes, you can do the form 1 without having the upper.
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twodollarbill
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by twodollarbill »

You may use that lower with a 16" upper until your paperwork approves.
Change your Buffer to an heavier H2 if you have problems.
You can use conversions with your new 5.56 SBR lower.
Pretty sure you have to use 6.8 mags for reliable feeding.
usmcvet0331
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by usmcvet0331 »

Not sure who AA is.

I use an H2 buffer with my 11.5" uppers. It will help with bolt bounce. You may not need or want to upgrade. It depends on other things like your gas port size.

I se AA is Adam Arms. I was thinking Ancil Arms but they're outta business.
bunker168
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by bunker168 »

AA = Adams Arms
usmcvet0331
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by usmcvet0331 »

Buffers are cheap enough to try out. If you can borrow that's even better.

http://m.youtube.com/#/watch?desktop_ur ... Nv28&gl=US
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markm
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by markm »

Any upper that requires a non standard USGI action spring is garbage. I'm not familiar with this Adams Arms nonsense. I think I know a guy who has one that works.
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renegade
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by renegade »

bunker168 wrote:I got an Adams Arms 16" tactical full rifle

Down the road I will SBR it with an AA 11.5" upper.

While waiting for my suppressor form 4 to go through can I also do form 4 (I hope that's the same form for SBR) on my AA lower receiver?
It is a different form, but similar.

Generally it is a good idea to make/register your SBR before you have the short upper. So you are GTG in this regard.
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by dvanncvann »

markm wrote:Any upper that requires a non standard USGI action spring is garbage.
I have several AR's in different calibers that I use non USGI springs in. Don't make them garbage. USGI parts were designed around 5.56x45. Some of us like other calibers.
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PAIN
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Re: Can I register my ar15 lower receiver as SBR w/o 11.5"u

Post by PAIN »

Yes, by law you form 1 your lower. Once the stamp arrives, you then purchase your barrel / upper.

I run the standard buffer and buffer spring on my 11.5 AR15 SBR. The buffers job is to control cyclic rate of machine guns....

I'm not experienced in the 6.8 so I can't say anything on that.

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