Pistol AR-15 - I'd like some thoughts from y'all

[Mac11FA]

I recently read a surprisingly well written article about the usefulness of AR pistols (can't remember which website).
In the past I hadn't been a fan of the idea, especially since you couldn't set the thing to your shoulder, and I thought the ballistics of a .223 from a barrel shorter than 16" would be stupid.

But this article changed my mind. The writer talked about the merits of having a rifle-caliber firearm in a smaller package that could be concealed legally in a backpack, and also brought the cogent point that in many states it is illegal to travel with a loaded rifle. A loaded pistol, however, falls under the reciprocity of our CCW permits.

I tell you all of that to get to my question: What barrel length do you think is the shortest that will still give me decent terminal ballistics?

I'd like to go as short as possible. I looked at 10" barrels and decided with the 8" upper attached it would never fit into a backpack, especially with any muzzle device attached. If I ever decided to put a suppressor on it, it would take too long to assemble if I needed it in a hurry.
So I'm trying to find that sweet spot between concealabilty and velocity.
Also appreciate any thoughts on lightweight options, muzzle devices, sights, buffer tube covers, etc.

Unless you have a really big backpack, no matter how short the barrel, simply not going to conceal in backpack. Take the length of the buffer tube, the length of the lower and upper without the barrel and you will see that you are already behind the eightball. Look at ballistic performance of round you intend to shoot and go with barrel that is long enough to stabilize the round. Since it looks like you are building a .223/5.56 chambered rifle you may not want to go much shorter than 7.5" barrel (never research just guessing) and if you intend to shoot suppressed there are many options out there to achieve both.

This is why many folks stuck with pistol calibers when building an SBR. Another option would be the CZ Evo Scorpion:

 

[Righter13]

Do a 10.5" barrel with a law folding stock.

If you plan to shoot suppressed and unsuppressed check out the Innovstive Arms W.A.R. upper.

I've heard great things about the gen tech Suppressor BCG as well but have no experience with it.

 

[Leshaire]

Do a 10.5" barrel with a law folding stock.

If you plan to shoot suppressed and unsuppressed check out the Innovstive Arms W.A.R. upper.

I've heard great things about the gen tech Suppressor BCG as well but have no experience with it.

I have also heard good things about that Gemtech bolt and carrier but havent seen one with more than a few mags through it, so Im wondering how they perform over time after a lot of rounds.

 

[Righter13]

I have also heard good things about that Gemtech bolt and carrier but havent seen one with more than a few mags through it, so Im wondering how they perform over time after a lot of rounds.

Garry Marr has one on his channel "tremis dynamics" that he swears by and has a pretty high round count with it suppressed.

 

[Axeman]

Garry Marr has one on his channel "tremis dynamics" that he swears by and has a pretty high round count with it suppressed.

OK, I saw the video, and yeah, that's interesting - but what about using an adjustable gas block like Superlative Arms? Supposedly theirs doesn't send the extra shit (gas and junk) back to the BCG at all. And then you CAN switch to suppressed without breaking down the gun.
BTW, any reason you couldn't run in suppressed mode on that BCG all the time? He never mentioned that.

 

[Axeman]

Do a 10.5" barrel with a law folding stock.

If you plan to shoot suppressed and unsuppressed check out the Innovstive Arms W.A.R. upper.

I've heard great things about the gen tech Suppressor BCG as well but have no experience with it.

Know anything about the DOLOS QD barrel system? Maybe a better plan than the LAW folding stock?

 

[Mac11FA]

OK, I saw the video, and yeah, that's interesting - but what about using an adjustable gas block like Superlative Arms? Supposedly theirs doesn't send the extra shit (gas and junk) back to the BCG at all. And then you CAN switch to suppressed without breaking down the gun.
BTW, any reason you couldn't run in suppressed mode on that BCG all the time? He never mentioned that.

Can you easily access the adjustment screw on the gas block? No? Reason the war upper is popular.

 

[Axeman]

Can you easily access the adjustment screw on the gas block? No? Reason the war upper is popular.

Can you easily access the adjustment screw on the gas block? No? Reason the war upper is popular.

Now that I look at it I remember I've seen this before, back when I wasn't interested in pistol or suppressor.
Well, I've grown up a bit.
One thing they don't mention is what happens to the extra gas - where is it vented?

 

[Red Dawn]

Now that I look at it I remember I've seen this before, back when I wasn't interested in pistol or suppressor.
Well, I've grown up a bit.
One thing they don't mention is what happens to the extra gas - where is it vented?

I think that most of the excess gas will go out ejection port and some down the lower at the magazine connect. Depending on your gas block you may see some sign of a small leak there. The WAR upper allows less wear and recoil also about 2db quieter at the shooters ear.

 

[Axeman]

I think that most of the excess gas will go out ejection port and some down the lower at the magazine connect. Depending on your gas block you may see some sign of a small leak there. The WAR upper allows less wear and recoil also about 2db quieter at the shooters ear.

Neat. I'm sold on the WAR upper. Now I gotta find a barrel with gas port specs in line. Most places selling "lower cost" (cheap) barrels don't list many specs at all. This is turning into quite a research project!! And I haven't even tried getting into weight-saving issues yet, other than deleting any "arm-braces" and going with a paracord-wrapped buffer tube.

Question regarding gas blocks (please endure the story before the question): My first build I bought a cheap aluminum gas block. Several hundred rounds later I decided to build a second AR, and swap barrels (my first barrel was a cheapo I got off eBay), and I noticed erosion in the gas block where the port didn't line up perfectly. Also noticed leaks.
For my second/rebuild of the rifle, I got a much better barrel (5R rifling, .223Wylde chamber, etc.) I went with a YHM clamp-on gas block, and was so happy with the fit that I've used them ever since on my other builds.

But I've ALWAYS seen leaks at the gas block, as well as at the front of the upper where the gas tube enters.
Is this normal? Am I doing something wrong? Should I be using some sort of sealant/better barrel/better gas block? Is there a lightweight gas block that will be good for this build?

 

[Leshaire]

Neat. I'm sold on the WAR upper. Now I gotta find a barrel with gas port specs in line. Most places selling "lower cost" (cheap) barrels don't list many specs at all. This is turning into quite a research project!! And I haven't even tried getting into weight-saving issues yet, other than deleting any "arm-braces" and going with a paracord-wrapped buffer tube.

Question regarding gas blocks (please endure the story before the question): My first build I bought a cheap aluminum gas block. Several hundred rounds later I decided to build a second AR, and swap barrels (my first barrel was a cheapo I got off eBay), and I noticed erosion in the gas block where the port didn't line up perfectly. Also noticed leaks.
For my second/rebuild of the rifle, I got a much better barrel (5R rifling, .223Wylde chamber, etc.) I went with a YHM clamp-on gas block, and was so happy with the fit that I've used them ever since on my other builds.

But I've ALWAYS seen leaks at the gas block, as well as at the front of the upper where the gas tube enters.
Is this normal? Am I doing something wrong? Should I be using some sort of sealant/better barrel/better gas block? Is there a lightweight gas block that will be good for this build?

I'm 99% sure it's not supposed to be leaking. @Wallace built mine and during some preliminary testing it was sealed tight. No air was getting out anywhere. Harder to tell during actual shooting.

@DarthVader was the brains behind most of mine too.

@Righter13 would also likely know.


I'm sure one of them can chime in here though.


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[Axeman]

I'm 99% sure it's not supposed to be leaking. @Wallace built mine and during some preliminary testing it was sealed tight. No air was getting out anywhere. Harder to tell during actual shooting.

@DarthVader was the brains behind most of mine too.

@Righter13 would also likely know.


I'm sure one of them can chime in here though.


Sent from my ObamaPhone using Tapatalk

How I can tell it's leaking it the spray of fine black crud that mists along the barrel at the leak, and gathers on the inside of the handguard.
Hasn't affected operation, though, all of mine run great, including the .308 I built. I thought maybe it might make a difference in a suppressed gun, though

 

[DarthVader]

How I can tell it's leaking it the spray of fine black crud that mists along the barrel at the leak, and gathers on the inside of the handguard.
Hasn't affected operation, though, all of mine run great, including the .308 I built. I thought maybe it might make a difference in a suppressed gun, though

Gas and carbon residue where the gas tube enters the upper receiver, is normal. Severity will depend on the ammunition and how large the gas port is. A small amount of gas leakage / blowby where the tube enters the gas block is also normal. It usually self seals with carbon after a few hundred rounds. That is, unless the tube/gas block are out of spec. If the tube does not fit tightly upon install, something is off.

Now that we have the normal stuff out of the way, gas leaking from the gas journal area isn't normal. There can be a small amount of blowby on a new build. But it should be minimal and stop over time. If it's excessive, either the gas journal / GB tolerances are too loose or the GB / port aren't aligned. The gas block should be a tight fit when sliding it onto the barrel. If it just slips on and spins freely, it's too loose. Yes, you can make it work. But the idea is to achieve as tight of a gas seal as possible. I recommend BCM gas blocks for this reason.

The erosion you witnessed is exactly why aluminum gas blocks are for retards. NEVER use an aluminum gas block. See example below:

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[DarthVader]

Finally, I'm not a fan of clamp on gas blocks. They can shift. That's bad. A properly installed low profile block is easier to install and exponentially stronger / more reliable. By properly installed, I mean dimpled barrel + degreased threads + loctite 262. I think I wrote a tutorial about it somewhere on here a while back.

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[Wallace]

Gas and carbon residue where the gas tube enters the upper receiver, is normal. Severity will depend on the ammunition and how large the gas port is. A small amount of gas leakage / blowby where the tube enters the gas block is also normal. It usually self seals with carbon after a few hundred rounds. That is, unless the tube/gas block are out of spec. If the tube does not fit tightly upon install, something is off.

Now that we have the normal stuff out of the way, gas leaking from the gas journal area isn't normal. There can be a small amount of blowby on a new build. But it should be minimal and stop over time. If it's excessive, either the gas journal / GB tolerances are too loose or the GB / port aren't aligned. The gas block should be a tight fit when sliding it onto the barrel. If it just slips on and spins freely, it's too loose. Yes, you can make it work. But the idea is to achieve as tight of a gas seal as possible. I recommend BCM gas blocks for this reason.

The erosion you witnessed is exactly why aluminum gas blocks are for retards. NEVER use an aluminum gas block. See example below:

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What he said^^^^

 

[Righter13]

Know anything about the DOLOS QD barrel system? Maybe a better plan than the LAW folding stock?

No experience with dolos but I'd rather ensure the barrel is locked up tight each time. AND the law is quicker to deploy.

 

[Righter13]

Finally, I'm not a fan of clamp on gas blocks. They can shift. That's bad. A properly installed low profile block is easier to install and exponentially stronger / more reliable. By properly installed, I mean dimpled barrel + degreased threads + loctite 262. I think I wrote a tutorial about it somewhere on here a while back.

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Agreed. To add on I prefer a pinned block. Especially Noveske when I don't have to install it.

@DarthVader

 

[Axeman]

Gas and carbon residue where the gas tube enters the upper receiver, is normal. Severity will depend on the ammunition and how large the gas port is. A small amount of gas leakage / blowby where the tube enters the gas block is also normal. It usually self seals with carbon after a few hundred rounds. That is, unless the tube/gas block are out of spec. If the tube does not fit tightly upon install, something is off.

Now that we have the normal stuff out of the way, gas leaking from the gas journal area isn't normal. There can be a small amount of blowby on a new build. But it should be minimal and stop over time. If it's excessive, either the gas journal / GB tolerances are too loose or the GB / port aren't aligned. The gas block should be a tight fit when sliding it onto the barrel. If it just slips on and spins freely, it's too loose. Yes, you can make it work. But the idea is to achieve as tight of a gas seal as possible. I recommend BCM gas blocks for this reason.

The erosion you witnessed is exactly why aluminum gas blocks are for retards. NEVER use an aluminum gas block. See example below:

Sent from my SM-G955U using Tapatalk

OK, thank you for being very specific there. I did ditch that aluminum gas block when I rebuilt that rifle, I figured if that much had eroded so quickly it couldn't be good. Plus, since on a PISTOL build we've now learned that the barrel pressures are MUCH higher at "uncorking", this means gas port pressures will skyrocket in a shorter barrel - thus, I'll look to save weight elsewhere.
I can't help but wonder why so many companies sell products that are just junk. It can't be that much cheaper to cast it out of AL instead of steel!
As for the clamp-on, I did that because I'd noticed the dimples on the barrels didn't always line up with the set screws on the GB, figured to go another way. But now I see there are tools to make new dimples in the right place for each GB, so I gotta get one of those.

 

[Axeman]

No experience with dolos but I'd rather ensure the barrel is locked up tight each time. AND the law is quicker to deploy.

Before I heard about the Dolos system I seriously considered DRD. But I really hated their rail, and how heavy it is, (and EXPENSIVE with a proprietary upper!) so I went a different route - bought a DRD barrel nut (hand-tighten!) and carefully fitted my nice carbon-fiber handguard on it. It worked fine, but since I had to use an allen-wrench to remove the handguard, it wasn't really a QD system. I was trying to figure out a better way when I ran across the Dolos, and it seemed like they'd already leapt ahead on the same path I was on.
To the point, I never had problems with that hand-tightened barrel nut trying to loosen. And since my rail was screwed into the nut, my front sight would have moved if there was a problem.
But I did get tired of worrying about it so I switched back to a standard nut and that's how my 2nd AR sits right now. Lesson learned - it's not good to have something I worry about going wrong.

 

[Axeman]

By the way, it's GREAT to have all of you giving me your advice.

THANK YOU!!!!

I'll certainly have to let you all know what I eventually build, and post pictures...

But we're not done yet.

So far I know I need:
WAR upper receiver
10.5" barrel with gas port for suppressor (not sure which manufacturer)
A good quality suppressor (suggestions that make sense for this build?)
QD muzzle device for suppressor
Pistol length buffer tube with paracord cover
LAW tube folding kit
Geissele SSA-E trigger (I used them on my .308 and long-range 5.56 and fell in love)
YHM Extended takedown pins (I put these on all of my builds)
KNS Anti- rotating hammer/trigger pins (I put these on all of my builds)
10" Carbon-fiber handguard (I think Delta Team Tactical has them on sale for $46)
Standard BCG
Pistol length gas tube
STEEL low-profile gas block
Dimple-making tool
LPK (they're pretty much all the same, aren't they?)
80% lower
pistol grip (likely one with the reduced grip angle)
Maybe a TRS-32 red-dot

Suggestions?
Did I miss anything?