What Piston upper, full auto sbr

[Jgunner]

I have a colt m16 coming and been thinking about going piston upper for the usual reasons. Ill be wanting 2-3 separate uppers. 2-556 and one 300bo

I run 5.56 10.5 daniel defense di uppers now, but looking to try something different. I will be exclusively shooting suppressed, not AGAINST going a little longer in barrel, but 12.5” is about as far as ill go for now.

I will be using this for coyote hunts and pig hunts when i feel like it.

I looked at lwrc, lmt, pws, sig and pof. I have not ran any piston system other than a sig i borrowed from a buddy and never shot it supressed. Sig in my eyes is at the very bottom end of the spectrum.

Flame suit on!!!

 

[davsco]

range i helped out at had a lwrc piston upper on a rental m4. not suppressed, but zero issues and i'm not sure it ever got cleaned. i've used my full lwrc m6 dmr rifle at a bunch of 3 gun matches with zero issues, other than the time i had the ejection port jammed against a barricade...

 

[Jgunner]

range i helped out at had a lwrc piston upper on a rental m4. not suppressed, but zero issues and i'm not sure it ever got cleaned. i've used my full lwrc m6 dmr rifle at a bunch of 3 gun matches with zero issues, other than the time i had the ejection port jammed against a barricade...

From my reading, suppressed and short are the problem. I had my eyes set on building a hk416 but then parts dried up, people “said” it would be way over gassed suppressed and short without a vented gas block. But i have ZERO real world experience with any of it and no friends with anything of substance. Dropping 2k on an upper to find out it won’t run right would drive me mad.

 

[MPDS13]

I have both LWRC and PWS. Both shoot great and have been extremely reliable. Adjustable pistons help with gas blow back. But, nothing is going to get rid of the gas, it it is less with those two rifles. It also depends on what suppressor you are using.

I have never shot a LMT, but I’ve heard they are very over gassed with suppressors and need to be tuned. I had a Sig MCX and it shot great. But was a little grassier than my LWRC and PWS.

 

[Jgunner]

I have both LWRC and PWS. Both shoot great and have been extremely reliable. Adjustable pistons help with gas blow back. But, nothing is going to get rid of the gas, it it is less with those two rifles. It also depends on what suppressor you are using.

I have never shot a LMT, but I’ve heard they are very over gassed with suppressors and need to be tuned. I had a Sig MCX and it shot great. But was a little grassier than my LWRC and PWS.

What length barrels on your two?

 

[CrabsandFootball]

HK is the only one I would trust. It was specifically designed for High round count, SBR and Suppressed use without tearing the rest of the gun apart. Delta Boys worked with HK to come up with that mousetrap and its why its used by certain units.

Otherwise just get some cheap 11.5" uppers and burn them up.

 

[Jgunner]

HK is the only one I would trust. It was specifically designed for High round count, SBR and Suppressed use without tearing the rest of the gun apart. Delta Boys worked with HK to come up with that mousetrap and its why its used by certain units.

Otherwise just get some cheap 11.5" uppers and burn them up.

Ill give them another look. Its tough building 3, but i will prob buy 1 soon, run it, see if i like it and continue onward. Going from 10.5 on my original search that has expanded to 12” might make my life easier. I do love my hk clones, they just run.

 

[CrabsandFootball]

Yea the increased dwell time going from a 10.5 to 11.5 is like 40%, much less violence on the action. A 12.5 would be even better.

If you are doing mag dumps on FA just expect to see issues with gas port erosion. It will drastically reduce the life of the barrel depending on how hot you get it.

Gas management is the other issue.

If it was me, I would instead look for a belt fed upper. They are around $3-4K but much more fun. I mean you already dropped 20K+ on the lower, so why the fuck not right?

Own the Most Affordable Belt-Fed AR Upper in the World – SHOT Show 2019

FightLite Industries’ MCR-060 claims to be the lightest belt-fed upper receiver assembly and it will fit any AR15, M16, or M4 lower receiver.

www.gunsamerica.com

FIGHTLITE INDUSTRIES MCR BELT-FED UPPER RECEIVER FULL AUTO | Brownells

The FightLite Industries MCR Belt Fed AR-15/M16 Upper Receiver allows you to convert your AR-15 or M16 from a standard, magazine fed rifle, into a multi-purpose belt-fed, that can also feed from a magazine. Simply attach the upper as you would any...

www.brownells.com

 

[Jgunner]

Yea the increased dwell time going from a 10.5 to 11.5 is like 40%, much less violence on the action. A 12.5 would be even better.

If you are doing mag dumps on FA just expect to see issues with gas port erosion. It will drastically reduce the life of the barrel depending on how hot you get it.

Gas management is the other issue.

If it was me, I would instead look for a belt fed upper. They are around $3-4K but much more fun. I mean you already dropped 20K+ on the lower, so why the fuck not right?

Own the Most Affordable Belt-Fed AR Upper in the World – SHOT Show 2019

FightLite Industries’ MCR-060 claims to be the lightest belt-fed upper receiver assembly and it will fit any AR15, M16, or M4 lower receiver.

www.gunsamerica.com

FIGHTLITE INDUSTRIES MCR BELT-FED UPPER RECEIVER FULL AUTO | Brownells

The FightLite Industries MCR Belt Fed AR-15/M16 Upper Receiver allows you to convert your AR-15 or M16 from a standard, magazine fed rifle, into a multi-purpose belt-fed, that can also feed from a magazine. Simply attach the upper as you would any...

www.brownells.com

Haha, yeah, something like that! I just want to be able to hunt with it without looking like i am looking for Predator. Haha.

Problem i see if i go 416 is actually getting barrels. Maybe they are not all that special and a daniel defense or some other high quality barrel can be used/retrofitted. I do not mind buying barrels when they go, as long as its not a difficult job to get a new barrel! I do not plan on doing mad mag drops like i am trying to kill it, just enough to put a smile on my face. Around the same time my mac10 f/a should be in my possession and that IS made for mag drops. Its 45acp, but ill do a 9mm conversion for shits and giggles.

 

[CrabsandFootball]

If you get a real 416 barrel they will be chrome lined hammer forgered. Depending on your firing schedule , 20-30k rounds should be doable.

at $300 a case your talking $6-9k in ammo.

 

[MPDS13]

What length barrels on your two?

PWS MK111 and MK114
LWRC 14.7 and 10.5

the PWS upper function great on my registered lower. Though I have not put real high round counts through them or did multiple mag dumps in a row.

 

[Strangedays]

I used to own a POF that was great. It adjusted easy for suppressed or not.

 

[RyanScott]

The 416 has its own peculiarities. For instance the original ones were 1100 rpm suppressed which is why CAG got PMAGs. Also why the SF -212 replaced the original K. If you can’t get one with the Aubert and Duval barrel don’t bother with them.

A piston system isn’t inherently more reliable, and the M4 doesn’t have a reliability problem it has a durability problem. And a problem being fired when full of water.

 

[Jgunner]

The 416 has its own peculiarities. For instance the original ones were 1100 rpm suppressed which is why CAG got PMAGs. Also why the SF -212 replaced the original K. If you can’t get one with the Aubert and Duval barrel don’t bother with them.

A piston system isn’t inherently more reliable, and the M4 doesn’t have a reliability problem it has a durability problem. And a problem being fired when full of water.

My real complaint about hk416 is trying to get parts if something should happen to it. I try to make it a habit of avoiding difficult to obtain or extraordinarily expensive to repair/replace equipment. Guess this goes for most piston uppers.
I guess with cost/form/function does not exceed that of a standard di gun. you pay a lot for little gain.

Pof is close to me, i might stop in to talk to them, i kike the idea of the fluted chamber(kinda like a mp5/hk91 and that style of gun) but unsure if it actually helps or if its just a marketing gimmick. They seem to be the only company who does it.

 

[Tonsofguns]

Brownells sells barrels for the hk416 clones

 

[RyanScott]

POF, LaRue, HK and Hodge have flutes to one extent or another.

 

[Jgunner]

POF, LaRue, HK and Hodge have flutes to one extent or another.

Wasnt aware of others. Ill check em out.

 

[HornDog87]

From my reading, suppressed and short are the problem. I had my eyes set on building a hk416 but then parts dried up, people “said” it would be way over gassed suppressed and short without a vented gas block. But i have ZERO real world experience with any of it and no friends with anything of substance. Dropping 2k on an upper to find out it won’t run right would drive me mad.

Jgunner,

I have a hk416 upper that I pieced together with a vented block and it runs like a sewing machine. I don't have the real thing like your lower is, but I have a bfs3 and I can run the piss out of the upper with steel and brass case and zero problems. I'm running a spring CO green spring and vltor a5 buffer system in it. I think for the upper, I was able to put it together for around $14-1500. It is also a tack driver if I put some effort into it.

Semper fi
Horner

 

[Zero Fox]

I will throw my vote in for the PWS Mk111. The barrel is actually 11.85". I have the PRO version and kinda wish I had went with the Mk111 Mod-2. The PRO upper is good. The upper is extruded and just looks different and feels a little heavier. This is my second PWS rifle and not my last. The long stroke operating system is amazing running suppressed. I can't shoot full auto but I predominately shoot suppressed and the PWS system provides the best experience I've had. I also picked the PWS Mk111 PRO up for $600 so that's a plus.

 

[tacops1]

This is easy ...noveske chrome lined barrel w switch block

 

[CrabsandFootball]

This is easy ...noveske chrome lined barrel w switch block

2005 called and is asking to speak with you.

 

[Blaster7Romeo]

I know a guy with a hk416 upper for sell lol

Accessories - SOLD: HK416 AH OTB upper Geissele rail and extras

SOLD HK 416 AH date code so it has OTB upgrades and has the lighter profile barrel. I have the factory hand guard, Factory sights, HK buffer and spring, extra firing pin, Geissele Rail in FDE With Arisaka Surefire scout light mount. And Brownells BRN stripped lower I was going to get it...

www.snipershide.com

I like lwrc as well.. I even shot the barrle out my lwrc and never had a single malfunction. Sent the upper back to lwrc they put in a new barrle turn around was about 4 weeks during the holidays. The problem with lwrc is the gas vents under the handguard so it will vent on your hand depending on your grip. Check out LMT but the problem there is I had trouble finding one when I was looking

 

[tacops1]

2005 called and is asking to speak with you.

Hahahahaha you got me and Maybe so but if it’s not broke don’t fix it

Outperforms anything you mentioned and is more accurate I hate personally hate piston guns although I respect that’s what the op asked for. But piston guns are less accurate wether they stay cooler or cleaner I will chose to clean my gun more n handle the heat for the direct impingement accuracy ...this is the reason LWRC broke into the direct impingement world they are made in my home town ...Noveske Rifleworks prob has “one of” the best chrome lined barrels on the market today hands down lasts forever as well as being extremely accurate. I only had one upper from them in 6.8 I didn’t care for n sold

I mean why did A certain ops groups have so many reliability issues with Hk 417’s yes the 417 they started using Wilson Combat recon rifles ? Maybe the 5.56 HK 416 did better than the 7.62 417 but it’s still concerning

 

[RyanScott]

The difference between piston and DI is overstated, and at least one JSOC unit went back to DI guns. The HK416 advantages are almost all in materials science. Except for that shooting when full of water thing.

 

[Rancid Coolaid]

Sig does product development along the way; as such, the 516s and 716s have improved dramatically with age. I have several of both and run them quite happily - and reliably. Granted, I am not dumping 10 mags as fast as I can load them; but they have run a fair bit and given me no issues.

They have the gas block figured out and they run hella cleaner than a DI SBR, especially in high humidity environments.

And Sig has sales from time to time, and the SBR uppers are usually heavily marked down.

I agree entirely that volume of fire uppers should be best you can afford; sigs are reliable and dependable for my needs. But I'm not Delta.

 

[never_summer]

This was a while back but I use to have a 7.5” Adams arms piston upper on my m16. Ran reliably but the cyclic rate was unreal at that short of a barrel. I’d personally tune it on a mid length 14.5” DI system and clean more.

 

[RyanScott]

I don’t know why carbon fouling is such a concern, no decent gun is going to stop from it in twice as many rounds as anyone will actually carry.

 

[CrabsandFootball]

SigUSA uses customers as beta testers and virtually every product they have released since Cohen took over has been a massive piece of shit that required new revisions or they scrap the whole product and come out with something new. SigUSA is a trash company, Yugo quality at BMW prices. Want a real sig? buy german or swiss.

The switchblock was the first "durable" adjustable has block for hard use. Its so obsolete and overpriced its not even worth considering. Not to mention Noveske quality and engineering took a massive nose dive when John died, a decade ago. They haven't come out with one relevant product since johns passing, unless piss poor machined $300 lowers or tactical hammers are your thing. As a company, they aren't even worth looking at today.

 

[tacops1]

SigUSA uses customers as beta testers and virtually every product they have released since Cohen took over has been a massive piece of shit that required new revisions or they scrap the whole product and come out with something new. SigUSA is a trash company, Yugo quality at BMW prices. Want a real sig? buy german or swiss.

The switchblock was the first "durable" adjustable has block for hard use. Its so obsolete and overpriced its not even worth considering. Not to mention Noveske quality and engineering took a massive nose dive when John died, a decade ago. They haven't come out with one relevant product since johns passing, unless piss poor machined $300 lowers or tactical hammers are your thing. As a company, they aren't even worth looking at today.

I do agree with ya after the Johns passing thing... I’m just lucky to own several guns John was apart of and they shoot amazing. My friend just got their N6 .308 gas gun and gets .50 @ 100 which is damn good compared to most gas guns

I love LWRC I just couldn’t get past a 3k rifle for an 1” group or slightly under when DD or Noveske and even HK did way better

 

[Jgunner]

Jgunner,

I have a hk416 upper that I pieced together with a vented block and it runs like a sewing machine. I don't have the real thing like your lower is, but I have a bfs3 and I can run the piss out of the upper with steel and brass case and zero problems. I'm running a spring CO green spring and vltor a5 buffer system in it. I think for the upper, I was able to put it together for around $14-1500. It is also a tack driver if I put some effort into it.
What barrel length and who’s barrels? The only ones i saw were not able to be used for suppressed unless its a zero backpressure. That keeps me from putting together an hk. Not sure if i could take a good high quality barrel and have a gunsmith make it work, but it sounds harder than its worth to me at this time.
Semper fi
Horner

What length barrel and who’s barrel? The ones ive seen are not designed for suppressors with back pressure.

 

[Jgunner]

The difference between piston and DI is overstated, and at least one JSOC unit went back to DI guns. The HK416 advantages are almost all in materials science. Except for that shooting when full of water thing.

I am not completely opposed to staying di, but if for a couple grand i can make life easy, then i would do it.

 

[RyanScott]

Yeah the HK is backpressure sensitive.

 

[Blaster7Romeo]

I am just going to throw this out there... may not be exactly what you want.

BUT I just got an Sig mcx virtus.. and seem to be liking it so far. It is verry presently gassed with a suppressor.. they said they built them from the ground up for a can. And I believe them.. if you get an upper kit from sig it comes with the butt stock adapter to make it a folder. Problem will be finding the right hammer to trip the firing pin safety or take it out (like you would have to do with a hk416). There is a thread in the Sig section on ARFCOM about it ..

 

[Rancid Coolaid]

SigUSA uses customers as beta testers and virtually every product they have released since Cohen took over has been a massive piece of shit that required new revisions or they scrap the whole product and come out with something new. SigUSA is a trash company, Yugo quality at BMW prices. Want a real sig? buy german or swiss.

The switchblock was the first "durable" adjustable has block for hard use. Its so obsolete and overpriced its not even worth considering. Not to mention Noveske quality and engineering took a massive nose dive when John died, a decade ago. They haven't come out with one relevant product since johns passing, unless piss poor machined $300 lowers or tactical hammers are your thing. As a company, they aren't even worth looking at today.

Good to know you have strong opinions. I agree on the sentiment but not on the conclusion.

But carry on.

 

[HornDog87]

What length barrel and who’s barrel? The ones ive seen are not designed for suppressors with back pressure.

My barrel is a hkparts 10.4" barrel, been pretty solid.

 

[Jgunner]

My barrel is a hkparts 10.4" barrel, been pretty solid.

You shooting It suppressed?

 

[shoobe01]

Proper length and piston-or-not has come up on some other forums where many of the people shoot guns that are not theirs, so have more than two safety switch settings.

• DI seems to have no notable downsides for short and full auto. Quality manufacturer, everything set for the barrel length, is more important than the system itself.
• 12.5" (really, 11-14") seems to be the sweet spot for SBRing a 5.56. Much shorter and things get more abusive to you and the gun.

FWIW: I have a (hardly ever full auto because I don't own such a lower) 12.5" BCM that is both pretty delightful to shoot, and also is exactly what a few others use with claimed great joy and happiness. No adjustable blocks or anything, just the silicone charging handle "gas seal," and it runs like a top when quiet or loud.

(For comparison, I do have an adjustable gas block .300 and a custom drilled gas regulator for my 5.56 SIG-55x and those are notably more awesome when suppressed, but if you wear real eyepro and it's anything but totally still out, gas face off the DI 12.5" 5.56 is not a problem at all. Wouldn't know to complain if I didn't have the others.)

...If it was me, I would instead look for a belt fed upper. They are around $3-4K but much more fun. I mean you already dropped 20K+ on the lower, so why the fuck not right?

Also, yeah. I'd get a lot of uppers if I could ever swing an MG lower. Belt fed is a lot to fuss with though so I think find or replicate one of the Colt LMGs like the Canadians bought, and some C-mags or something.

 

[HornDog87]

You shooting It suppressed?

Yes sir! About 90% of the time, I run a rugged surge 7.62 with a 556 end cap and anytime of Ammo people want to put through it. Although I barely use it anymore, I might be switching to lmt since I have an MWS.

Semper fi
Horner

 

[Jgunner]

I have exclusively ran 10.5’s the last 5 years on my quest for light weight and compact. It has beat up a couple things but anyone who holds one says “damn, it feels like a toy, does it work?” Lol. Yeah, killed a lot of critters with them. That being said, i want a little longer barrel. I will try a 12.5 out.

 

[Jgunner]

In a more information full reply to this topic:

1. I have shot maybe 50 different platforms suppressed. Working as the gunsmith at a shooting range, you get a LOT of "my suppressed thingy doesn't bang more than once - HELP!"
2. The AR's vary in their performance under suppression. The buffer/BCG/Gas port really makes a difference.
3. The BEST DI setup is one that is ported properly or has adjustable gas, and is rocking the Surefire BCG/Spring setup. It has a longer cam pin stroke so it opens later, reducing your gassing dramatically. Add to that enhanced buffering on the BCG and you get close to nirvana.
4. Gas buster type charging handles WITH silicone are the top of the line for gas control in the face.
5. Not every piston gun does well, frankly. I think how much you get gassed depends a good bit on when the bolt opens, and if its early suppressed you still get smoked. For example, my Sig MCX 11.5" smokes badly with higher power ammo, even with a gas buster and piston setup.

I was thinking about a bcg, ill look at those surefires. Charging handle as well, as i have seen them, just never tried one out. They are both things i can play with while waiting for my stamp to show up.

Ever try those pigtail gas tubes? I know they were mentioned previously in here, not sure if they even do anything, but i have zero experience in them.

 

[RyanScott]

Pig tails are tourist traps.

 

[Thorbeast]

Are you certain you want a piston AR? Battlefield Vegas has been pretty open about their experience running hundreds of thousands of rounds through full auto ARs, and they've been very underwhelmed by every piston AR they've had on their line (including the HK).

Also, anything you can do to delay the unlocking of the bolt and slow down the cyclic rate is going to make the weapon more reliable and more controllable. I think you'd be well served by a 14.5 mid length, but if you have to have a shorter barrel. I think a 12.5 with the surefire OBC would be a great setup. Alternatively, LMT's enhanced BCG has an elongated cam pin path to delay the unlocking of the bolt, if you paired that with Vltor's A5 buffer system, Tubb's flatwire spring and an adjustable gas block you'd have a great setup for full auto.

 

[Jgunner]

Are you certain you want a piston AR? Battlefield Vegas has been pretty open about their experience running hundreds of thousands of rounds through full auto ARs, and they've been very underwhelmed by every piston AR they've had on their line (including the HK).

Also, anything you can do to delay the unlocking of the bolt and slow down the cyclic rate is going to make the weapon more reliable and more controllable. I think you'd be well served by a 14.5 mid length, but if you have to have a shorter barrel. I think a 12.5 with the surefire OBC would be a great setup. Alternatively, LMT's enhanced BCG has an elongated cam pin path to delay the unlocking of the bolt, if you paired that with Vltor's A5 buffer system, Tubb's flatwire spring and an adjustable gas block you'd have a great setup for full auto.

No, not married to the idea after this thread. Not trying to reinvent the wheel either. If i can make di work better, than its what I’ll stick with.