AR Pistol OAL, barrel length question(s)

71Chevelle427 · Feb 20, 2019

Never tried an AR pistol "build" before, and could use some clarification on some measurements that are, or can be, a little confusing....

Thinking of using a complete lower setup, like pictured below (APF lower w/SIG brace), in .223/5.56, nothing else...

I think OAL has to be UNDER 26" to remain a PISTOL and not turn itself into an SBR, correct?

No desire for an SBR, tax stamp and all that...just want to do an easy-peasy AR pistol, as in complete lower, and possibly complete upper, and snap the pins in and go shooting...

If that (<26") is the case, what length barrel would all but guarantee not going over that dimension?
I was thinking most, if not all, 10.5" uppers would fit the bill, but want to be sure.

Also, is the 10.5" barrel, the best choice for the pistol buffer and if .223/5.56?

outrider58 · Feb 20, 2019

71Chevelle427 said:
Never tried an AR pistol "build" before, and could use some clarification on some measurements that are, or can be, a little confusing....

Thinking of using a complete lower setup, like pictured below (APF lower w/SIG brace), in .223/5.56, nothing else...

I think OAL has to be UNDER 26" to remain a PISTOL and not turn itself into an SBR, correct?

No desire for an SBR, tax stamp and all that...just want to do an easy-peasy AR pistol, as in complete lower, and possibly complete upper, and snap the pins in and go shooting...

If that (<26") is the case, what length barrel would all but guarantee not going over that dimension?
I was thinking most, if not all, 10.5" uppers would fit the bill, but want to be sure.

Also, is the 10.5" barrel, the best choice for the pistol buffer and if .223/5.56?

There is no ninimum length for an AR pistol in Md, so you're GTG there. You could even put a folder on it, as pistols do not have stocks, per se.

A 10.5" barrel will be fine. Any shorter and your gun might get a little picky when it comes to .223 Rem ammo.

DutchV · Feb 20, 2019

There might be a rule like this in Michigan but not in Fed or MD law.

dreadpirate · Feb 20, 2019

I personally would not get a 5.56/223 in anything less than a 10.5" barrel due to the drop in bullet velocity.

babalou · Feb 20, 2019

Also 300 blackout likes around 8.5-10 inch barrels. .223/5.56 a little longer iirc. Chadmeister had acpost on optimal pistol lengths with calibers.

71Chevelle427 · Feb 20, 2019

outrider58 said:
There is no ninimum length for an AR pistol in Md, so you're GTG there. You could even put a folder on it, as pistols do not have stocks, per se.

A 10.5" barrel will be fine. Any shorter and your gun might get a little picky when it comes to .223 Rem ammo.

Thanks for the replies, guys. Looks 10.5" will be the barrel length.

Maybe I worded it wrong, but I was more concerned (SBR-wise) with a 10.5" barrel and the shoulder brace being a factor in making it TOO LONG. Are you saying the "shoulder brace" length doesn't matter, since it isn't actually a "stock"? The OAL was my main concern.

Thanks.

outrider58 · Feb 20, 2019

71Chevelle427 said:
Thanks for the replies, guys. Looks 10.5" will be the barrel length.

Maybe I worded it wrong, but I was more concerned (SBR-wise) with a 10.5" barrel and the shoulder brace being a factor in making it TOO LONG. Are you saying the "shoulder brace" length doesn't matter, since it isn't actually a "stock"? The OAL was my main concern.

Thanks.

Going too long with the barrel/gun(over 26") could move you from pistol to rifle, but not with a 10.5" barrel because your brace(pictured) doesn't appear to be extendable.

It wouldn't be an AOW unless you added a VFG to a pistol shorter than 26" OAL.

Sent from my SM-G965U using Tapatalk

3paul10 · Feb 20, 2019

ok, I think its been covered before...but what about an AR pistol with a 14.5 inch barrel?

dontpanic · Feb 20, 2019

3paul10 said:
ok, I think its been covered before...but what about an AR pistol with a 14.5 inch barrel?

Absolutely legit.

The only length issue with pistols is that >26" you can install a VFG. Otherwise it does not matter at all.

This article does a pretty good job of describing the rules for pistols and AOWs
https://www.thefirearmblog.com/blog/2016/10/18/aow/

3paul10 · Feb 20, 2019

Thanks!

Biggfoot44 · Feb 20, 2019

I can't speak to State Law in every State , but for Feds and Maryland , no such thing as " Too Long " .

If the OAL should exceed 26in , then it would become an * Other Firearm * , not an SBR . Many people do this on purpose , to be able to use a vert foregrip .

If an "arm brace" were to cross the line to being considered a shoulder stock , the SBR issues would be triggered by that , not whether < or > 26in OAL .

Vjornaxx · Feb 20, 2019

According to this document released by the ATF (PDF warning - LINK), section 2.1.4 states:

The overall length of a firearm is the distance between the muzzle of the barrel and the rearmost portion of the weapon measured on a line parallel to the axis of the bore.

This is interpreted to mean the measurement of OAL is taken from the end of the threads (or permanently attached muzzle device) to the end of the EXTENDED adjustable "stock." (More support for this HERE)

So, with a 10.5" barrel and a fully extended brace, the 26" OAL should not be an issue to meet. Furthermore, when the firearm is over 26" OAL, it is no longer a pistol and is instead just a "firearm" which means you can put a vertical grip on it.

71Chevelle427 · Feb 20, 2019

Awesome info. Thanks everyone!

dmable44 · Feb 20, 2019

Have plans to build a pistol with an SBA3 brace and was wondering similar things. Thanks for the info

71Chevelle427 · Feb 21, 2019

Biggfoot44 said:
I can't speak to State Law in every State , but for Feds and Maryland , no such thing as " Too Long " .

If the OAL should exceed 26in , then it would become an * Other Firearm * , not an SBR . Many people do this on purpose , to be able to use a vert foregrip .

If an "arm brace" were to cross the line to being considered a shoulder stock , the SBR issues would be triggered by that , not whether < or > 26in OAL .

So, I could use a 14" or even a 16.5" barreled upper, as long as the Sig Brace hasn't been outlawed YET?

I may slow down my hunt for a "pistol" upper, if I can test-fire the pistol lower with one of my existing AR (rifle length) uppers....or should I not do that?

Also, since it will be a pistol, I "assume" barrel marking/description makes no difference? As far as HBAR, heavy barrel, blah, blah, blah ?

Biggfoot44 · Feb 21, 2019

Yes , yes you could .

Vjornaxx · Feb 21, 2019

71Chevelle427 said:
So, I could use a 14" or even a 16.5" barreled upper, as long as the Sig Brace hasn't been outlawed YET?

I may slow down my hunt for a "pistol" upper, if I can test-fire the pistol lower with one of my existing AR (rifle length) uppers....or should I not do that?

Also, since it will be a pistol, I "assume" barrel marking/description makes no difference? As far as HBAR, heavy barrel, blah, blah, blah ?

Yes, you can slap any upper on a lower registered as a pistol/firearm (NOT a rifle) as long as it doesn’t have a VFG on it. If it does, see my above statement.

However - for the purposes of testing reliability, you’re going to want to tune the buffer to the final upper you decide to put on it. A 10.5” is going to cycle differently than a 16.1” on the same lower.

And yes, since it is not a rifle, it is not subject to the restrictions put on rifles such as barrel weight. There are other restrictions such as VFGs - again, see my above statement.

KP Shooter · Feb 21, 2019

My vote would be to stick with a 11.5" upper. Recoil impulse will be significantly less due to a longer dwell time. This will save the life of your internals. Ditto the above comment about having to tune your buffer to whatever upper you decide to mate with it. H2 is probably a good place to start.
Do you plan on suppressing it?
Also, take a look at Gearhead works Tailhook Mod2. If you look around, you should be able to find it for $150. If you want the link for where I last saw it, message me. I have two of them and They are truly solid pieces of kit. They also have an approval letter from the ATF. The tube is proprietary, so you cannot find just any ol' stock on it. Since their brace is the only thing that will fit, I guess it made the ATF happy.

If you are going to buy one pistol lower, might as well buy 3

71Chevelle427 · Feb 21, 2019

Thanks again. On this one, I'll likely just get the 10.5, or 11.5, barrel and be done with it.

I have no desire to use a VFG on anything, rifle or pistol, so no worries there.

Also, no intention of suppressing anything.

Thinking since every one of my lowers started life being built as pistols, I may just switch them back at some point.

71Chevelle427 · Feb 28, 2019

Vjornaxx said:
So, with a 10.5" barrel and a fully extended brace, the 26" OAL should not be an issue to meet. Furthermore, when the firearm is over 26" OAL, it is no longer a pistol and is instead just a "firearm" which means you can put a vertical grip on it.

Thanks again for the replies, links and info...

Attached pics of the final-ish product...

Alex Pro Firearms multi-cal lower
SB Tactical SBM4 pistol stabilizing brace
Radical Firearms 10.5" 5.56 1/7" Twist Upper w/ FCR M-LOK Rail
Bushnell TRS-25 Red Dot

I definitely intend to upgrade the plain jane grip, just haven't decided, what with, yet.

OAL is 28.5"...

Going to try it out today.

AR Pistol OAL, barrel length question(s)

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