is there a max barrel length for an AR pistol?

MG-70 · Jun 10, 2021

I know it's too early to be thinking about this, but I'm trying to figure out how best to use a couple of AR receivers bought as a receivers and assembled as braced pistols using KAK braces on smooth receiver extensions.

Q1: Is there a max barrel length allowed in MD for pistols without a brace?

Q2: Is there a max barrel length allowed for a "MD SBR"? I believe 29" or "More than 29"" OAL to be the shortest.

Q3: Is OAL measured from end of receiver extension to end of muzzle, not counting muzzle device unless it's permanently attached?

If my legally assembled pistols are redefined by the Left as an SBRs, then my plan is to simply remove the braces, as opposed to paying the tax stamp to help pay for Uncle Joe's horrible spending of other peoples' money. If removing the braces still makes the kitties sad, then I'll just build some more non-offense heavy barreled rifles, or buy some Chinese throwing stars or something.

Thanks in advance for any helpful replies!

PS. I wonder if I held on to the tubular pipe insulation and single point slings...if they only focused their efforts on enforcing the laws currently in the books they'd make a much greater positive contribution to society!

erwos · Jun 10, 2021

IANAL:
1. I believe the answer here is "no".
2. Yes. That would be a 15.999" barrel.
3. Rifles are measured from the the tip of the muzzle (not muzzle device) to the end of your stock fully extended, or to your receiver extension, if you don't have one. MD measures the same way as the Feds. There has been some debate about how the Feds measure guns with braces, and I believe it is "fully collapsed".

Personal opinion, but form 1 SBR is the way to go.

outrider58 · Jun 10, 2021

MG-70 said:
I know it's too early to be thinking about this, but I'm trying to figure out how best to use a couple of AR receivers bought as a receivers and assembled as braced pistols using KAK braces on smooth receiver extensions.

Q1: Is there a max barrel length allowed in MD for pistols without a brace?

Q2: Is there a max barrel length allowed for a "MD SBR"? I believe 29" or "More than 29"" OAL to be the shortest.

Q3: Is OAL measured from end of receiver extension to end of muzzle, not counting muzzle device unless it's permanently attached?

If my legally assembled pistols are redefined by the Left as an SBRs, then my plan is to simply remove the braces, as opposed to paying the tax stamp to help pay for Uncle Joe's horrible spending of other peoples' money. If removing the braces still makes the kitties sad, then I'll just build some more non-offense heavy barreled rifles, or buy some Chinese throwing stars or something.

Thanks in advance for any helpful replies!

PS. I wonder if I held on to the tubular pipe insulation and single point slings...if they only focused their efforts on enforcing the laws currently in the books they'd make a much greater positive contribution to society!

Q1) Not that I'm aware of.

Q2) 29" is the minimum requirement for a center-fire, semi-automatic SBR's over all length. There is no maximum length, although once your SBR reaches or passes 16" barrel length, it is no longer considered an SBR. SBRs in general are governed by barrel length except in MD where they have a minimum length requirement(it's stupid).

Q3) Mind you, there is no minimum length requirement for pistols. They can be as short as you want.
SBR's, as previously enumerated, are measured from the terminal(permanent) muzzle to the end of the stock at its fully extended length.

erwos · Jun 10, 2021

One other thing: in MD law, your gun is an SBR due to configuration, not due to paperwork. So this thing people want to do where they register their AR15 as an SBR and then build it however they want with an 16" barrel because "it's an SBR" is not a workaround to the HBAR requirement. Just getting ahead of that.

outrider58 · Jun 10, 2021

erwos said:
One other thing: in MD law, your gun is an SBR due to configuration, not due to paperwork. So this thing people want to do where they register their AR15 as an SBR and then build it however they want with an 16" barrel because "it's an SBR" is not a workaround to the HBAR requirement. Just getting ahead of that.

Exactly. SBR= barrel shorter than 16"

Pinecone · Jun 11, 2021

One thing, the 29" minimum is not just for SBRs. ANY semi-auto, centerfire rifle needs to meet that minimum length.

MG-70 · Jun 11, 2021

Thank you all for the clarifications!

I'm still unsure whether OAL needs to be over 29" or whether 29" makes the cut for a MD SBR. Anyone know the shortest 5.56 AR barrel length, Milspec 6-position receiver extension, and Magpul CTR combination that makes the cut?

Also, the stock in it's fully extended position requires further research in coming up with a suitable solution, if I decide to join the SBR owners group. I know Voltr has longer receiver extensions, and I've seen some Chinese samples on ebay as well.

I need to research the intricacies of having an SBR, other than the $200 tax stamp, the wait for the paperwork approval, and the need and expense of having someone engrave the lower with my personal info. I know there are some travel restrictions, the need to request permission to travel out of state (?), but I don't know what happens if I move out of the state, for example. I'm not one bit worried about the gov knowing what I own; they've known for years, they probably know more about what I have in the house than my wife does, and she's the quiet, nosey, type.

This year, I sold a 9mm pistol upper and Hahn mag adapter that I'm pretty sure would've passed the 29" MD rule, thinking of replacing it with a 8.5"-9" upper to go with a Foxtrot Mike dedicated Glock lower. I know I'll be able to shoot braceless pistols (with just the receiver extensions), but if I want to future proof them for eventual MD SBRs, then I have to make sure they make the 29" OAL. These days decent handguards cost more than lower receivers and barrels, and since I'm a cheap bastard, I like to plan things out. With my luck, and the current administration, I'll probably end up having to assemble something very similar to what I sold.

I'm not trying to bypass any Hbar rules; I'm trying to stay ahead of the possible new ones. As for Hbars, "I got f'ing Hbars coming out of my F'ing ears!"

I hope everyone has a safe and pleasant weekend!

outrider58 · Jun 11, 2021

A 10.5" barrel will get you past the 29" mark with a standard carbine 6 position buffer tube. There are gyrations you can go through to get a shorter barrel, but for 5.56, you really don't want to go shorter than 10.5"

Using a standard 6 position tube, in order to reach the coveted <29" mark, you will need at least an 11"+ 9mm barrel. That's just the way they measure out. You could overcome that with other buffer tubes though.

MG-70 · Jun 11, 2021

outrider58 said:
A 10.5" barrel will get you past the 29" mark with a standard carbine 6 position buffer tube. There are gyrations you can go through to get a shorter barrel, but for 5.56, you really don't want to go shorter than 10.5"

Using a standard 6 position tube, in order to reach the coveted <29" mark, you will need at least an 11"+ 9mm barrel. That's just the way they measure out. You could overcome that with other buffer tubes though.

That's what I had on the upper I sold, an 11" Ballistic Advantage barrel. My understanding is that when measuring for a handguard, you should subtract 1/2" from the OAL of a 9X19 barrel to make up for the chamber, which is machined out of the barrel, as opposed to a separate extension.

Thanks again for the quick reply!

Biggfoot44 · Jun 12, 2021

No Maximum bbl length for Pistols , the T/C Contender is 16.25 in bbl.

No. Max bbl length for SBR in Md ,but there is a potential Catch- 22 between State and Federal . A centerfire Semiauto with 16 in bbl , but OAL greater than 26 inch , but less than 29.0 inch . Illegal as a Rifle in MD , but not meeting either Federal criteria to be SBR .

Sh00bs · Jun 15, 2021

i was under the impression pistol's were also sub 16" ? who is walking around with a 20" barrel pistol ?
My ar pistols do Not have stocks (since they arent SBR's) nor do they have braces (thankfully with that new ATF bs), they're just foam coated. so what makes it a pistol then? just the designation when i purchased it ? i registered it as O for other and that was that... i was told if i was building it under 16" it would be a pistol or sbr if i put a stock on it.
so with no stock/brace on the back, what's the difference from a pistol/rifle ? 16", no ? - and the classification on the paperwork lol

Biggfoot44 · Jun 15, 2021

More too it than that .

In Federal Law a key factor is OAL of over or under 26 inches .

OAL under 26 , " designed to fire with one hand " aka no stock , = Handgun , even if bbl over 16in . Examples - Super 16 Contenders , various bolt action and single shot pistols designed for IHMSA Unlimited and Hunting .

Over 26 OAL , no stock is " Other Firearm " , even if bbl under 16in .

FrankAR15 · Jun 17, 2021

Isn’t there a “minimum length” in MD for SBR’s?

For instance, the Springfield Saint Edge PDW has a 5.5” barrel and with brace In collapsed position is 18.75” and fully extended 23.5”

Could you even SBR that pistol in MD?

outrider58 · Jun 17, 2021

FrankAR15 said:
Isn’t there a “minimum length” in MD for SBR’s?

For instance, the Springfield Saint Edge PDW has a 5.5” barrel and with brace In collapsed position is 18.75” and fully extended 23.5”

Could you even SBR that pistol in MD?

There is for center fire semi-auto SBRs. It must be over 29"(measured with stock fully extended).

Generally speaking, in an AR15 style SBR, a 10.5" barrel will get you there with most calibers. Many pistol calibers will require an 11" barrel or an extended buffer tube or a permanently extended stock.

FrankAR15 · Jun 17, 2021

outrider58 said:
There is for center fire semi-auto SBRs. It must be over 29"(measured with stock fully extended).

Generally speaking, in an AR15 style SBR, a 10.5" barrel will get you there with most calibers. Many pistol calibers will require an 11" barrel or an extended buffer tube or a permanently extended stock.

It has a special compact BCG and an
Integral to Maxim Defense buffer tube, I think I would have to rebuild the whole pistol. It’s all designed to run the 5.5” barrel.
Do I have any other options?

Dme8199 · Jun 17, 2021

Also want to know if there are any options. I have DDM4 PDW 7" 300 blackout.

outrider58 · Jun 17, 2021

FrankAR15 said:
It has a special compact BCG and an
Integral to Maxim Defense buffer tube, I think I would have to rebuild the whole pistol. It’s all designed to run the 5.5” barrel.
Do I have any other options?

Do you run it suppressed? I've seen suppressor shrouds that can be pinned and welded to your barrel. Once added, the barrel length will extend to the end of the shroud. The suppressor screws into the shroud.

outrider58 · Jun 17, 2021

FrankAR15 said:
It has a special compact BCG and an
Integral to Maxim Defense buffer tube, I think I would have to rebuild the whole pistol. It’s all designed to run the 5.5” barrel.
Do I have any other options?

Dme8199 said:
Also want to know if there are any options. I have DDM4 PDW 7" 300 blackout.

I have the same problem with my AR9 pistol. I want to keep my 5" barrel, which is why it is a 'pistol' at this point. Once I get out of Merryland, I will simply SBR it.

erwos · Jun 17, 2021

The idea of producing SB-X style barrels for 5.56 and 9mm has a lot of merit in a post-brace era, and I'm surprised no one's tried doing so. In theory, you'd just thread it extra long, screw in the shroud, and then pin and weld it. Yeah, this basically forces you to put a can in it or look like an idiot at the range, but it's doable.

But if you just want a traditional-style PDW, you're pretty much screwed in MD if the brace ban becomes a thing.

SkiPatrolDude · Jun 17, 2021

MG-70 said:
Thank you all for the clarifications!

I'm still unsure whether OAL needs to be over 29" or whether 29" makes the cut for a MD SBR. Anyone know the shortest 5.56 AR barrel length, Milspec 6-position receiver extension, and Magpul CTR combination that makes the cut?

My SBR is a 10.3 in barrel with a standard carbine receiver extension. It was JUST under 29 OAL with a standard magpul stock, but with a B5 Systems Bravo stock, it is clearing at about 29.25. This is due to the larger butt pad on the stock and also where the adjustment detent is on the stock, which slightly increases length of pull. The B5 stock happens to be a very nice stock as well - one of my personal favorites next to BCM stocks.

You could always use an A5 buffer tube/buffer and rifle spring and you would be good to go with any stock.

is there a max barrel length for an AR pistol?

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