Piston-driven 300 Blackout

[DeputyDawg]

Hello everyone. I'm looking for a piston-driven 300 blackout upper with a 16" barrel. I've looked around a bit and am having very little luck. The only ones I can find are the BRN-180 but all are too short. I also found one but they were 1K+. BCA has side charging uppers but I'm not sure if that makes them piston-driven. Any help is appreciated.

 

[Tartakovsky]

Unless you go pistol length gas system, 300 blk out of an upper with a 16” barrel doesn’t make much sense, hence why you’re having such a hard time finding a piston driven one.

 

[DeputyDawg]

So would a side charging handle like this be a piston upper?
BC-15 | .300 Blackout Upper | 16" Parkerized Heavy Barrel | 1:8 Twist | Pistol Length Gas System | 15" MLOK

 

[Mtn_Guy]

So would a side charging handle like this be a piston upper?
BC-15 | .300 Blackout Upper | 16" Parkerized Heavy Barrel | 1:8 Twist | Pistol Length Gas System | 15" MLOK

Pistol length gas system, 16” upper? Pass.

Why go carbine length in .300BLK?

 

[Marty McFly]

Pistol length gas system, 16” upper? Pass.

Why go carbine length in .300BLK?

I'm going to sbr an ar10 lol why not

 

[EddieCoyle]

Pistol length gas system, 16” upper? Pass.

Why go carbine length in .300BLK?

Pistol length in a DGI is the only one that works with everything. I don't know about the performance in a piston upper.

 

[LittleCalm]

Why not just DI for 16” and if you want piston go SBR with an upper like PWS.

 

[ffej ruedorb]

I just returned a BRN-180 in7.62x39 to Brownells. The quality of the upper is real bad for the price point. The bolt guide spring has no retention and flies out. Also the bolt and charging handle is sloppy.

Pistol length gas system is absolutely what you want

 

[Tartakovsky]

I have a piston 11” HK416 upper in 300BLK. It runs supers great. It won’t cycle subs. And that’s an 11” barrel, never mind a 16” barrel.

 

[jkelly1229]

I'm going to sbr an ar10 lol why not

I always wondered why this didn't catch on over 300 blk... seems more versatile

 

[Joeldiaz]

Hello everyone. I'm looking for a piston-driven 300 blackout upper with a 16" barrel.

Here you go: Upper P2 300BLK 16″ AARS - Adams Arms

 

[Marty McFly]

I always wondered why this didn't catch on over 300 blk... seems more versatile

You seem....versatile......

 

[whatluck]

Why piston? Is it so it doesn't queef in your face every time you pull the trigger?

 

[Marty McFly]

Why piston? Is it so it doesn't queef in your face every time you pull the trigger?

I should call her

 

[DeputyDawg]

Pistol length gas system, 16” upper? Pass.

Why go carbine length in .300BLK?

Why piston? Is it so it doesn't queef in your face every time you pull the trigger?

I live in CT and without a ton of hassle, we can't really have pistol grips on AR anymore. So I was going to build a FightLight. I stumbled across this earlier today. Ranch Rifle Lower With Magpul 870 SGA Stock. It would save me about $400 if I could work out an upper.

 

[DeputyDawg]

Here you go: Upper P2 300BLK 16″ AARS - Adams Arms

Thanks. Very nice but a bit on the pricey side.

 

[42!]

I just returned a BRN-180 in7.62x39 to Brownells. The quality of the upper is real bad for the price point. The bolt guide spring has no retention and flies out. Also the bolt and charging handle is sloppy.

Pistol length gas system is absolutely what you want

That's weird, I've got 3 BRN-180s in 223, 300, and 7.62x39 and they all run flawlessly with excellent fit to Aero Precision lower, and great finish.

 

[ffej ruedorb]

That's weird, I've got 3 BRN-180s in 223, 300, and 7.62x39 and they all run flawlessly with excellent fit to Aero Precision lower, and great finish.

So if you split open any of your uppers the guide rod and springs won’t go flying across the room like a jack in the box wind up toy? My upper had just enough retention that I could open it and like a jack in the box it would spring out after opening. I don’t return anything but that upper was the worst firearm related purchase I ever made haha.

Also the 7.62x39 barrel dimensions were tight and restrictive for cast bullets

 

[42!]

So if you split open any of your uppers the guide rod and springs won’t go flying across the room like a jack in the box wind up toy? My upper had just enough retention that I could open it and like a jack in the box it would spring out after opening. I don’t return anything but that upper was the worst firearm related purchase I ever made haha.

Also the 7.62x39 barrel dimensions were tight and restrictive for cast bullets

There isn’t a retainer but my Armalite 180 doesn’t have it either so that’s true to the design. There is sufficient friction so they don’t go flying. I’m not sure if the HK variant of this action has a retainer.

As for your cast bullets, I haven’t seen or heard of any issues with manufactured bullets so there may be something there.

 

[MAGA99]

MCX VIRTUS UPPER ASSEMBLY - 16" 300BLK

Complete 16" upper assembly kit for your MCX Virtus chambered in 300BLK.

www.sigsauer.com

 

[Mesatchornug]

I live in CT and without a ton of hassle, we can't really have pistol grips on AR anymore. So I was going to build a FightLight. I stumbled across this earlier today. Ranch Rifle Lower With Magpul 870 SGA Stock. It would save me about $400 if I could work out an upper.

Piston v DI won't make that work.

Those lowers use a special BC, unless you put something like the BRN-180 upper on it, because it has the recoil assembly in the upper, not because it's a piston.

 

[MAGA99]

Virtus works on standard lower….

 

[DeputyDawg]

Piston v DI won't make that work.

Those lowers use a special BC, unless you put something like the BRN-180 upper on it, because it has the recoil assembly in the upper, not because it's a piston.

So piston-driven isn't the bufferless they are talking about?

 

[Mesatchornug]

So piston-driven isn't the bufferless they are talking about?

Correct.

The buffer assembly is what pushes the bolt carrier group forward to load the chamber with a new cartridge. In a traditional AR-15, this is in line with the barrel, behind the upper. In an upper like the BRN-180, the buffer system is in the upper receiver, above the bolt carrier group.

The piston system drives the bolt carrier group backwards, extracting the fired case. It replaces the direct impingement gas system that is traditional in the AR-pattern.

 

[LakeTrout]

Why piston? Is it so it doesn't queef in your face every time you pull the trigger?

I’m wondering why piston too and think it’s probably because there’s less gas in the face suppressed and probably slightly more quiet at the ear.

But a lot of this can be accomplished by a bleed off gas block in a DI system. And I would recommend that to the OP as a great alternative if the OP cannot find a piston system.

 

[Mesatchornug]

I’m wondering why piston too and think it’s probably because there’s less gas in the face suppressed and probably slightly more quiet at the ear.

But a lot of this can be accomplished by a bleed off gas block in a DI system. And I would recommend that to the OP as a great alternative if the OP cannot find a piston system.

because OP doesn't know what he's looking for.

 

[LittleCalm]

Correct.

The buffer assembly is what pushes the bolt carrier group forward to load the chamber with a new cartridge. In a traditional AR-15, this is in line with the barrel, behind the upper. In an upper like the BRN-180, the buffer system is in the upper receiver, above the bolt carrier group.

The piston system drives the bolt carrier group backwards, extracting the fired case. It replaces the direct impingement gas system that is traditional in the AR-pattern.

Some piston systems, like BRN that does not require a buffer tube, therefore allow for folding stocks. If you can house the buffer system in the upper like BRN, you get to use a real folder (not a LAW folder and the like). People say the BRN design is buffer-less in the sense that there is no need for a traditional AR buffer tube. It can be confusing. I assume Sigs are similar and also AKs?

 

[Mesatchornug]

Some piston systems, like BRN that does not require a buffer tube, therefore allow for folding stocks. If you can house the buffer system in the upper like BRN, you get to use a real folder (not a LAW folder and the like). People say the BRN design is buffer-less in the sense that there is no need for a traditional AR buffer tube. It can be confusing. I assume Sigs are similar and also AKs?

Sure, but that it's a piston is coincidental: there's no reason a DI system couldn't be built the same way.

Yes, the AK (long-stroke, piston) and Sig (short-stroke) designs also have their buffer in the receiver instead of hanging out the back (in a receiver extension).

Meanwhile, many (most?) of the AR piston uppers are not bufferless.

 

[LittleCalm]

Sure, but that it's a piston is coincidental: there's no reason a DI system couldn't be built the same way.

Yes, the AK (long-stroke, piston) and Sig (short-stroke) designs also have their buffer in the receiver instead of hanging out the back (in a receiver extension).

Meanwhile, many (most?) of the AR piston uppers are not bufferless.

Maybe they should call piston systems indirect impingement. What is gas blowback - is that just gases from the chamber blow a bolt back as opposed to a gas tube directing gas to the bolt?

 

[Noreaster]

I am surprised to hear negative on the BRN uppers. They are made by PWS. (now that i think of it, the praise i hear for the BRN uppers if from the PWS fan bois group)