SBR barrel length

[boothdoc]

So,
I am planning to go thru the SBR route and I am looking at the best overall barrel length.
From everything I have read 556 in a length of 11.5-14.5 can be accurate at a much longer distance then a barrel less then 11.5.
I was planning on going with a 10x scope with a offset red dot for close quarters target acquisition.

Can you change the barrel length after you get the approval.

I welcome all input and thank everyone for taking the time to school me.

 

[Bertfish]

You can change barrel length provided it can always be returned to its original configuration

 

[teratos]

So,
I am planning to go thru the SBR route and I am looking at the best overall barrel length.
From everything I have read 556 in a length of 11.5-14.5 can be accurate at a much longer distance then a barrel less then 11.5.
I was planning on going with a 10x scope with a offset red dot for close quarters target acquisition.

Can you change the barrel length after you get the approval.

I welcome all input and thank everyone for taking the time to school me.

You can put multiple uppers on the same SBR lower.

Very easy to return to the original configuration. You can do a 10.5” for close in work, 12.5/14.5” for more distance.

 

[calicojack]

You can put multiple uppers on the same SBR lower.

Very easy to return to the original configuration. You can do a 10.5” for close in work, 12.5/14.5” for more distance.

Yes, and you can register them all at the same time or add one or more afterwards. Just a change letter is required.

 

[teratos]

Yes, and you can register them all at the same time or add one or more afterwards.

Nope. No need to register anything else.

 

[outrider58]

Ask yourself, what is the purpose for this rife?

An SBR, in essence, is an entry weapon. It is made and designed for CQB. You should not be encumbered by velocity standards. An SBR is not made for long range applications. Velocity, in my view, is not a factor.

The only other consideration for an SBR is home defense. Either way, it is a rifle you will want to be able to move and deploy in tight quarters. As a home defense weapon, you will probably want to suppress it.

 

[outrider58]

Nope. No need to register anything else.

^^^This

As long as you keep the original barrel length(upper), and can always return it to its "original" form, no notification to ATFE is required.

 

[teratos]

Ask yourself, what is the purpose for this rife?

An SBR, in essence, is an entry weapon. It is made and designed for CQB. You should not be encumbered by velocity standards. An SBR is not made for long range applications. Velocity, in my view, is not a factor.

The only other consideration for an SBR is home defense. Either way, it is a rifle you will want to be able to move and deploy in tight quarters. As a home defense weapon, you will probably want to suppress it.

I believe a suppressed SBR to be an almost ideal HD gun.

 

[boothdoc]

Outrider58,
Very good points.
All, thanks for the input

 

[Cwarnick]

11.5 - 13.7 would be my vote for SBR. beyond that i would pin and weld to 16" and no stamp.
otherwise just keep the brace, put that tax money towards a good brace and muzzle device.
Or just get a can thats 30 cal capable and you can cross platform it with 556/300blk/308

i personally have a 13.9" 556 and a 10" 300 blk. both pistols with sba4/sba3.

i would get a can before an sbr stamp.

 

[boothdoc]

I have the cans I need for any build I need.

I want a SBR for home defense and oh course for target shooting

 

[teratos]

I have the cans I need for any build I need.

I want a SBR for home defense and oh course for target shooting

10.5” will work with certain stocks. With a can it comes out to 17”…very manageable.

 

[Cwarnick]

an a5 intermediate buffer like vltor, solgw, and bcm will take some of the harshness out of it similar to a rifle buffer, but still keep carbine stock compatibility. helps with the short barrel gas issues.

 

[teratos]

an a5 intermediate buffer like vltor, solgw, and bcm will take some of the harshness out of it similar to a rifle buffer, but still keep carbine stock compatibility. helps with the short barrel gas issues.

…and are a little longer to squeeze out more OAL.

 

[calicojack]

You know you can also go 10.5" for 300 Blackout and (say) 12.5" for 5.56.

 

[calicojack]

Nope. No need to register anything else.

Well - ok I suppose there is no advantage to registering multiple length uppers but you can if you want. Not sure about different calibers, but maybe you are not interested in that anyways.

 

[boothdoc]

I was thinking of the A5 tube setup

 

[teratos]

I was thinking of the A5 tube setup

Then you are golden with 10.3”+

 

[alucard0822]

There are 2 ways to go about it. Either keep the original upper with you, or send a "please amend my form 1 with these additional configurations" letter, and swap whatever uppers you want whenever you want. I send a letter with a list of the uppers I might swap to, and just keep a copy of the letter with a copy of my NFA forms in my range bag. You are only required to Notify rhe ATF if you change the configuration permanently, and there is a bit of grey what that means, swapping uppers at the range, swapping at home, etc. I just mail a letter, cheap insurance IMO, and i can just keep my SBR lower on whatever upper I want. https://www.guntrustguru.com/how-do-i-change-the-registered-configuration-of-my-short-barreled-rifle.html

If you are stuck with the 29" OAL thing, that is a 10.5 or larger. A 10.5 is a fine 5.56' barrel length, especially with heavier bullets or suppressed. Ends up about the same size as a 14.5-16" AR with a can, and will clear a 9" handguard. 11.5 and 12.5 are hot now, they add about 100fps per inch in that range( 10.5 is about 2500FPS with 55gr), once you get to 14.5" there isn't a ton of barrel length saved for the $200 tax stamp vs 16". 300BO really starts to get fun under 10", and subs are awesome down to < 7" barrels, but they are too short for MD. 22 uppers are a ton of fun, especially suppressed, and you can tuck a 5" can in 7" handguards pretty well with a 4.5" barrel.

 

[Biggfoot44]

It isn't just velocity per se , it's the dwell time .

10.5 to 11.5 is modest change in velocity , but significant % increase in dwell time . This can allow for the gas system configuration to be more flexible and forgiving for better reliability and consistency .