Delta's DI vs Piston AR15 (SFOD-D) [Range Talk] 

On a swat team, I carried a 14.5 inch M4, fixed carry handles until I finally converted them to flat top A1s. We were originally issued Beretta PM12S, then M16A1s and several MP5A4s. I preferred to carry my 14inch Benelli M1 Super 90 on entries until I became a sniper. Man, those were fun times but it was mid 90s to mid 2000s.

@@Mag_Aoidh Had to go feast my eyes on that Benelli, had never crossed my mind that Swat would use a 14" variant. What a kickass little hammer of a shotgun. Would love to own one! Was it a 4 + 1 ?

There is a reason Soviets had their insane reliability testing for AK and why vast majority of their gear is tested to operate between -50C and +50C.

Teflon teflon teflon.

Yeah, moving from the arid Australian bush to Switzerland, I can never get used to running rifles with oil/grease in them. We just avoided it and ran dry or with graphite/teflon powder.

I carried an M4/Mk18 as 11 and 18 series for over 30 total months in combat (Iraq/Afghan). Never once had a malfunction with thousands of rounds fired 🤷‍♂️ Edit: every malfunction was either user or magazine induced.

@@DraegerV1 That’s cool, but I can also say that I’ve been a proud owner of many budget rifles and pistols over the years including hi-points and I’ve too shot tens of thousands of rounds through them without ever experiencing a malfunction. Anecdotal experiences don’t necessarily make something true.

@@kilo0151 Nope. But it does contribute to the law of averages.

yeah each has thier application

thats tied into corruption, the so called "meat on the bone" in small arms parlance. If the budget and will is there they would all buy knights or Big G.

Ak’s are better

@@Dylan.More-Veiny They are so good that there are like 2 or 3 countries (besides Russia of course) who are adopting new AKs as their military firearms. It's an outdated platform.

@@foleymajanywhere really really cold lol. Do Alaska state troopers still use AKs?

They were having carry handles machined off and Weaver rail sections drilled and tapped onto the uppers right around the time of the XM4 testing, then just went to M4A1s. Guys who still liked the carry handles kept the detachable handles on and used the Delta Cheek pieces on Fiberlite Stocks. When shooting with NODs, they’ve been using LAMs even since Desert One days. PAQ-4C was really common in the early 1990s before they asked for AIM-1 IR Laser power, but in a smaller box with an illuminator, which became the PEQ-2A. There are some really cool set-ups with no internet photos of the early 1990s carbines that rival a lot of what’s out there right now, other than the PAQ-4C. Drop an NGAL onto one of those free-floated 723 Carbines with AEM suppressor and you’d be doing better than 99.99999% of AR-15s.

LAM is better than any optic under nods

They werent shooting with their optics under NV. None of the red dots available at the time were compatible with NV devices. It was active aiming only with PAQ-4s and later PEQ-2s.

Matt pranka of xrayalphallc has stated recently that nobody there buys into the riser concept, it goes as far to call it gay

@@nickcurrier8074 Kyle Lamb said it was just what they had back with the carry handle uppers, not intentional. Once they saw the Colt ACR submission, they might have been instrumental in steering the XM4 program into going with the detachable carrying handle and proper height optics mounts relative to solid cheek position with a helmet. Early XM4s were basically 727s anyway. I remember what a big deal the dual heat shield fat handguards were in 1994-1997. CAG mostly skipped past them to Unit-built modded FF tubes off SR-25s, KAC RIS, MRE, FF RAS, and all types of mounts for Aimpoints, S&B Short Dots, LAMs, and clip-ons.

Trapped in 1960. My g3 has this annoying thing where if you don't modify it to ha e the proper roller gap and bolt handle gap, it literally cannot be unlocked no matter how much force you use.

Not an expert, but sounds like something is out of spec.

Same here with a lot of carbines run in extreme cold in Finland from 2005-2016. 11.5”, 14.5”, 16”, and 18” all ran great from -30˚C up to hot summers.

@@LRRPFco52How did you clean and lubricate your rifle? No lube, just CLP, or graphite?

I get it, in my opinion the solution is to set it up, maintain it and forget it. I use moly lube, loads that are standard and I expect results in extreme conditions, hot, cold, sand and wet. You never know, you work the day in a short sleeve shirt, go to bed, wake up with 2" of ice on the window and a steady 50MPH wind. Dealing with a 6ARC now too, testing is a bit difficult, I can't get far North or South and deep freeze units managed by gun enthusiasts aren't on every corner, but it keeps me off the strees and stops me from picking on the old people.

I thoroughly believe in the a5 system. With the tube, green springco and a5h2 every rifle I have with varying length barrels and gas lengths, supressed or not, any range of ammo just works in south Texas conditions. I just don't ever have cycling problems. A good armorer's course makes a world of difference

@@waltonchan3931 The Finns used WD40, CLP, and I used Slip2000 just because I could fly with it (non petrol based). Ran lots of high volume in 2-3 day courses in the dead of Winter there. TDP AR-15s/M4s ran just fine. Saw more issues with Arsenal AKs than anything. I did fragment my Gen 1 Magpul MIAD Grip. The little tabs broke off since the polymer became extremely brittle in -30°C.

Its more of matching the tool to the job. If you're CAG then you probably need an adverse gas position or just overgassed. If you're a competitive shooter then you want 0 recoil. If you're an average joe, if you have it reliable at your environment then you dont need adverse gas position so you're reducing your shootability in return for reliability that isn't needed. Just clean your guns and have a gun that shoots better. Recoil is always a negative and you should never accept more if you aren't getting something in return

You do realize as long as you use the proper gas system length in the AR the gassing isn't a problem? especially considering most ARs are 16 inch barrel. It's not an issue so there's no reason to have to extra weight and if you're really worried about it you can use the rifle length gas system and decent quality ammo it's really a no brainer.

@@fearsomefoursome4 I happen to live in a place where the climate can go from sand storms to snow storms and shockingly some of my lazier gassed rifles have a tendency to struggle with it. Moreover I'm just giving my two cents and personal preference, if you wanna use a dissipator go for it but I personally don't mind a rougher experience if it means more reliability. Again: AK Operator PSA AR torture test

I have a 5.56 Beryl AK that came from the factory a bit overgassed so I put a KNS adjustable gas piston in it. For range use, I run it gassed a bit higher than I'd like recoil-wise so that it runs flawlessly in normal conditions. But if I were in really cold or really hot weather? I'll damn near close the port so that mofo runs like a Swiss watch, recoil be damned. I feel like there is some weird reverse fuddlore going on in the gun community since the InRange mud test videos, as if a couple of videos shown in the same desert mud mean that every AR is flawlessly reliable in all conditions and the AK is just trash that jams when a light whiff of sand enters the action. I suspect the average off-the-shelf or built AR from the US commercial market would not actually run that well in adverse combat conditions because most are gassed very lightly; on the flip side, I've owned many European AKs and not a single one has EVER been "undergassed" and none have jammed (not counting the trial and error setting up my adjustable gas systems for my Beryl and M77). True military M4s and M16s would likely be properly gassed, as would piston ARs that almost all have adjustable gas settings.

@@flopus7 Recoil is always a negative, but reliability is not. I'll take a gun that hurts a little bit to shoot or has some muzzle rise but runs like Swiss watch over a competition-gassed AR made for split times. But yeah, I set my AK with a KNS to be slightly more heavily gassed than I need to run 100% in normal conditions for casual range use. If SHTF I'd close the piston almost entirely to ensure that bolt keeps slamming back and forth.

Or go with BRT custom spec gas tubes. They last a long time, especially for the vast majority of people.

Hang on a moment, everybody knows that Santa lives in Lapland!,

This is ironic because Stoner dabbled in all three main types of gas systems: DI/internal piston with the AR, the Tokarev-based short stroke with the AR-18, and even a long stroke for the Stoner M63. Even Stoner himself situationally thought pistons could be better. Really makes you think.

Look up the caracal 816 a2 small arms solutions you may be impressed by the improvements on the 416

How much of your issues are DI vs piston, or rather that the H&K 416 sucks? It is the most prevalent one out there, but militaries are also using LMT piston guns, Finland and Sweden are adopting piston guns from SAKO etc.

@@foleymaj The 416is clearly not a bad rifle, it’s just not my prefered rifle, i really don’t like this rifle, on lot of aspect : design, weight....but for sure yes, it’s reliable no doubts on it. Even i can see sometimes some malfunctions in the field, like failures too feed, even with this HK416F. If i could, i will change it for a DI gun, and i’m not the only one in my regiment ; this rifle has too much ergonomic issues and this is way too overgassed. Sometimes, we put some supressor on it just for fun, at the end of the day, and...it’s not fun, even with the "S" setting on, it’s gas, gas, gas in your face... It’s like the FN SCAR, yes lot of units, Armies, adopted it, but it’s not THE assault rifle, i believe it was tried by the Rangers in US Army, a long time ago, and they were not satisfied with it, for lot of reasons. We are, as soldiers, on the field, we eat, sleep, run, shoot....etc the rifle all day long, HK are good in marketing, but at the final, this we, soldiers, Who have to deal with all potentials issues of the gun. I kow there here lot of others piston guns in other Armies, but not because some others Armies adopted it that it’s a good rifle, or that Piston guns are, in every cases, they’re good piston guns, and they’re bad piston guns. Mort of the time it’s not because it’s not reliable, but because of others issues. For shooting with the 416F every day for 2 years now, except the good reliability, i don’t see the point with this gun, and i am also disappointed by the main feeling of the gun, and the poor ergonomics of this rifle, such as the left side magazine release, which can cause potentials big issues on the field (it’s already the case) and HK or not, it’s unacceptable to my mind. I know Armies have to deal with lot of considerations when they want to switch their service rifle, and they want reliability and it’s normal. But lot of Armies in the world still have their DI guns (especially USA, even if they’re switching now) and they’re not unreliable, or low tech guns. And there is always a difference between the marketing bullshit and the reality, always. In civilian shooting, to my mind, a 416 is useless, except if you are an HK fanboy or if you want this rifle because it’s look cool for you. The prices are way too high, and it’s just an AR15 with a piston.... But of course, it’s all personnal tastes, and it’s subjective, the principal is to have a rifle which fire everytime ;)

shut up

I was born and raised in NP AK and WE as kids in middle school would write back to those letters as Santa lolol

Kinda fuq'd I know. I graduated in 2005 so long time ago, not sure if they still do that shit but they'd have boxes and boxes of letters sent to "Santa" that we'd respond too in English class 😂

@@torranceparsons5216another NP local here, I was doing it in the 08-09 timeframe. I wouldn’t be surprised if it still happens lol

@@LostSourdough That's hilarious, never thought much of it when I was a kid doing it but thinking back it and saying it out loud it kind of seems messed up 🤣

sorta like how the m60 has a terrible reputation. they were so used and abused by that time , of course only those who used the clapped out ones had that opinion.

@@sabregunner1 The ar15 was designed with a piston and it was stripped out later for cost, thats why his next gun - the ar18 had a piston. There is some applications like over the beach, through the swamp applications where resistance to salt water corrosion and field expedient repairs of the operating system - may favor the piston gun.

@@Ravensbreak ok. i did say there may be situations in which one may be favored over the other depending on preference or situations in which one would be the better choice

@@sabregunner1 The biggest reason to use a piston system in an AR is for sustained automatic fire. Dumping mag after mag in the AR15 will result in a blown gas tube. But for most uses, especially in the civilian world, DI is more than adequate.

@@DriveCarToBar maybe this applies to my other comment not the one about used and abused military guns being the source of the "x is bad" because thats the version the person used

Piston rifles are more reliable

But that's wrong.

I prefer how smallarmssolutions says it, internal piston vs external piston

Yeah, it’s wrong, it’s good to me that he said internal piston, BECAUSE the non gun nerds probably don’t understand.

​@@meanman6992 For real, most people don't know what is meant

Gas operated or internal piston. Gas gun is also acceptable.

carrier tilt has been a solved issues for decades now

well clean both in the field and then its pretty clear what's superior for military use, for just plinking stuff on the range it makes no difference

​@@___seb3341 Get dirt and mud in the ejection port and see which is superior.

Carrier tilt isn’t a thing on piston ARs most of these issues came from DI guns converted to piston. Or just plane cheap piston rifles.

​@@southern842That is an extremely rare circumstance. It is also mitigated by dust covers

I thought that was a major driver for Delta. Water/mud/sand immersion testing was a huge part of the development of the HK416

It’s simply more reliable across the board. Only downside is weight.

​@@ZzBiohazzardzZExcept Socom dropped the Fat German for another fucking M4.

@@ravenwing199 Sorry, but they didn’t. DI is trash.

@@ZzBiohazzardzZ URGI is what they're using right this second. Almost like DI is able to be perfectly tuned for the load out needed.

No

Nice recovery. I've been pointing out for a long time that the AR-15 is not a direct impingement system as it's called forever, is incorrect. A piston is a piston wherever it's located.

Internal piston and direct impingement describe the same thing. The term internal piston is used by very knowledgeable people in the industry who do far more technical work with rifles than just selling products and shoot them, and describes the fact the BCG operates as the piston. The BCG inside the reciever in a DI rifle is an internal piston. The long/short stroke systems that sit under the handguard are external pistons.

@@mghegotagun The BCG in an AR15 operates as a gas cylinder. There is no piston that mechanically acts on any portion of the rifle. Gas alone provides the motive force. Gas goes in through the gas key and expands in the chamber created by the gas rings on the bolt, and the cylindrical shape of the carrier. The bolt is locked and immobile at time of firing. The only thing moving, is the carrier. It's a more complicated version of the gas system on the MAS-49.

Unit guys never used 723s or M4A1s on Full Auto. Larry said it was for handling different ammunition types when fired from short barrels and suppressed. They had tried 11.5” barrels since they always had a need for more compact carbines for low-vis work, but had issues with reliability as the round count stacked on the guns suppressed. I helped source some of the parts for him for early prototypes back in 2003.

Stoner himself made it pretty clear it isnt direct impingement. If it was DI there would be no gas rings on the bolt. The gas would just blow into the gas tube and push the carrier backwards like a MAS-49. The AR doesnt do that, it isnt direct impingement.

@@LRRPFco52 There's a video of him on RU-vid (maybe the interview with Ian McCollum on Forgotten Weapons??) explaining the full auto reasoning. Perhaps I'm not remembering correctly, and he mentioned other reasons. It's been a couple years since I watched it.

Cleaned a DI once. Not sure how they are supposed to clean that gas tube to maintain constant inner diameter. It was a one of those cqb 9mm paintgun training weapons. Im used to piston and rollers.

Thats why every DI system should have adjustable gas block. Pistons as well. First gen Hk416 didint have AGB. People play around with gas ports, springs, buffer weights, suppressors (flow etc.). All You need is adjustable gas block.

The 416 isn't much better suppressed. In fact, most of the recently retired US tier 1 guys trash it publicly.

Are you implying the higher pressure in shorter di gas systems makes longer dwell times less necessary?

nah it’s all good man!

@@cardboard_shaft fairy

@@shanecoolen3986 noveske is a g00ner brand, nothing more

I don't know the answer to that question. Arisaka makes the Midnight Mossy mount, it attaches to the front sight post, out front, over the barrel. I use a Surefire 300x on one, it's functional.

@alexanderm8880, from a gas system perspective, the T91 is good, but in a modern sense, it’s limited due to not being NVG friendly

@@donrichter3523 How so? Is it something to do with the handguard?

Correct, it's the CSAW program

I've seen a few videos on this. The mag gets so dirty it won't feed properly after a very short time.

@@jagx234 None of the videos Ive seen show that at all. Even in direct side by side comparison it doesnt get much more fouled whatsoever than just suppressed shooting.

The 90s definitely had a lot of stuff sitting on the shelf that should have been replaced but didn't. That was the issue with the 1911 by the time the m9 came around and was the issue with m9s after 30 years of use. There's also some unit and command politics at play in the budget process. When I was in the airborne we had fairly new stuff most of the time compared to other units.

I used all kinds of M16A1s, M16A2s, M4s, and M4A1s pre and post-GWOT. Lubed and fed from new or good conditions mags, they all ran just fine. Biggest problems were mags with split spines that double-fed, but you really had to take care of your magazines and then no real problems. We shot them all in pretty high volume. I took my M4 through a high volume course run by 3rd Group’s new CIF guys where I put 1100 rounds through it in about 4 hours. That was pre-SOPMOD heavy barrel, pre-H2 buffer, bone stock M4 with KAC RAS, PEQ-2A, Surefire, Aimpoint Comp M. Each one of us could shoot through a full can of 5.56 if we kept running drills. I had no malfunctions that I can recall. That was 2002. In Recon Platoons, we were burning a lot of ammo through M16A1s in the early-mid 1990s before we turned them in and drew out M16A2s. The M16A1 was better for weight, trigger, and balance for sure.

@@LRRPFco52 You had better luck than me. The first A2 I was issued would occasionally fire two rounds in Simi (happened right in front of a range office, he just shrugged and walked away). The second wouldn't go into battery unless you hit the forward assist. That was when it was clean and lubed (buffer spring needed replaced, good like getting the armorer to believe you that there was an issue). Good mags only helped, but only if the rifle was in good working order. Things are probably better on the ground side, but I was air wing and we were low priority on new gear. We still had people pulled for security detachments, and I've had several friends take and return fire, so wasn't entirely without consequences.

@@randomdude4505 Normal armorer inspections check the action spring length. If it’s too short, it needs to be replaced. I could see Air Wing getting shafted with weapons that were exposed to salt water and then components passed-down maybe. Number of cycles and any corrosion will wear out an action spring, but it takes thousands of rounds fired in short time or just neglect after saltwater immersion. Our A2s in Infantry OSUT were shot to crap, beaten up every cycle. Magazines were the main factor with them whether they ran or not.