Rotary Delayed Blowback: CMMG 9mm AR15 upper on WWSD 2020 lower

Well this got a lot steamier than expected, with all this talk or buts on the floor and giving them some umpf.

Cool

The default finish for WWSD rifles should be Hi-Point money.

"The button of doom" 🤣🤣🤣 That's pretty much how I feel about it. The forward assist is a pointless solution to a problem that doesn't exist. I've used Aero Precision "no forward assist" uppers on my last two builds and will probably do so with all of them going forward.

When you going to do a full video review of your personal WWSD?

Yeah that hesitation lock

Will you be coming to woodland brutality this may bloke?

While I think the Radial Delay sounds awesome, I was honestly pretty underwhelmed when I shot an acquaintances 10mm Banshee.

A friend had one of these and sold it recently. It absolutely didn't delay the bolt. The bolt went too fast and was very jarring and unreliable. He sent it back and they said the bolt was out of spec and replaced it. Same story with the new one. Had to add a bunch of weight to the bolt so it was heavy like a straight blowback. Recoil was intense. Very unreliable. Ejection pattern was everywhere from 12 to 6 o clock using the same ammo in the same mag in every test we did. Brass often hit the shooter. Brass got a lot of soot on it. It was fired unsuppressed.

I hated the thing. I bought a Stribog SP9A3 to test it out. It is delayed and has better mags and is a bit cheaper. Neither compare to an MP5. An MP5 or even MP5K with +p ammo is smoother than the Stribog with normal 9mm. A mule kicking me in the shoulder is smoother than that CMMG radial delay.

Seems like it would be a bit hard on the locking surfaces, good thing it's pistol calibre.

14:06 Normally blowback operated firearms do not need an extractor to operate*, because the case is being pushed out of the camber by the gas pressure in the barrel. The main problem is that the Banshee is a system designed for passive extraction (AR-15, M16) now converted to active extraction.

*Most blowback firearms only need the extractor for guidance of the self extracting case or for manually extraction.

Blowback is a Lie!

For about a year there has been a term circulating in the Internet, the term is “Blowback”. Nobody has ever heard of it, or knows what this is supposed to be. Is it a lie or does “Blowback” really do exist, meaning that we were unknowing all these years?

A “Blowback” operated firearm is supposed to be a form of self loading firearm with a fixed barrel, we all know als recoil operated. Weapons like Walther PPk, the Uzi, the G3 and others. This is supposed to be, because these weapons will work with blank firing adapters. By the way these adapters are muzzle diameter limitations that cause a back pressure that makes the firearms self loading mechanism work with black cartridges.

On a locked breech gun with slide locked only by springtention and the inertia of its mass, a self loading can not be achieved with a black firing adapter (Walther P38, FN High Power, TT-33 Tokarev, Ultrastar and others). Only these guns are supposed to be recoil operated.

One has to consider that there is a technical difference between Walther PPK and Walther P38. But every shooter knows that. He just named it differently. The PPK is a recoil operated and only locks by springtention and the inertia of the slide mass and the P38 is recoil operated with a tilting block lock. And there are mentions of “Blowback” in gun literature before the days of the internet. But only to be found in old military and police books.

The name “Blowback” is real.

But from a technical terming standpoint it does not matter if a weapon works with or without a blank firing adapter. All these weapons work according to the same physical principle of recoil. The fact that these weapons work with black cartridges does not justify to say, that they are excluded from the principle of recoil. The principle of recoil is a physical law. If you name it “recoil” or “pressure”, it's simply the same!

I own several pistols that are “gas delayed” and locked by springtension and the inertia of the slide mass. I know for a fact that the H&K P7 has a gasport. There gas is tapped to keep the bolt shut with the gas pressure. This is happening via a gas rod, until the bullet has left the muzzle. Only when the pressure has dropped, the slide will open drived by the recoil impulse. The technical background is that if the slide opens too fast a fireball will come out of the ejection port. If there would be a difference between “pressure” and “recoil” these weapons would not work at all! Vektor CP1, Norinco 77b and H&K P7 are proving that the differentiation between recoil operation and blowback operation is a Lie!

Blank firing guns for example do not have recoil. They are using the “back pressure” to cycle the slide back. The back pressure is dependent on several factors like the muzzle bore diameter. If one really wants one could name these weapons “Back Pressure Operated”. But only guns that are intentionally made to only fire blanks.

Has anyone of you ever heard of “Blow Back Principle”? It's just nonsense. If a projectile with a mass of x and a velocity a y is leaving a barrel, a certain recoil impulse is developed. If there would be “Blow Back” and “recoil” in addition, there would be two forces willing to open the slide of an Walther PPK. If this would be the case the slide would open way too fast before the Bullet could leave the muzzle, the pressure would remain too high and a fireball would shoot out of the ejection port.

I admit I was a bit mean in the text above by telling you that there are some mentions of a “Blow Back Operation” in literature, that may unsettled you a bit. But I assure you there is counter proof. You’ve not been unknowing and stuipid. In a book there is a Walther P38 described as “blow back”. This proves that the terms “Blow Back” and recoil mean the exact same thing. There is no difference.

Hecker & Koch manufactured the P7 as a recoil operated gun. The engineers were not to stupid to not understand firearm operations!

Conclusion: Either there is a person feeling very important lately because he thinks he knows something others don’t. Or some shooters have fallen for a hoax and this “person” has the fun of his life by watching the internet riddling his theory.

The term “Blow Back” exists. But the differentiation between “blowback operation” and recoil operation is a Lie! A thing like this just doesn't exist. The usage of the term “blowback” is confusing and is no longer in use for a reason.

I have a ke 9mm blowback ar. Some tuning things that help run those (i know its different than radial blowback). Are 5/8 inch spacers behind or longer vltor a5 buffers. The a5 buffer is also able to be heavier. You don’t need as much stroke to eject 19 mm brass as 45. For blow back i also use a 308 spring. I have a picture comparing it to a standard ar buffer and spring, but I couldn’t figure out how to post it here or patreon.

Good job Mike

Move your red dot forward.

Any wear on the locking lugs in the barrel extension? Seems like the corners are getting hit by the bolt every shot.

Does it stretch brass? 0.1" of straight blowback against a ~1oz bolt seems rough.

Fired one of these. Very smooth recoil. Liked it

"Bolt picking Bloke", I see what you did there.

So you are aware, I discussed it with CMMG, snd they said an ideal ejection pattern on one of these is ejecting to 3:00 to 3:30, and a 4:30 means the bolt is traveling faster than is ideal.

LAPD just had a case where an officer with a M4 missed, shot through the wall, and killed someone else. This would be a great option for cops already carrying M4s for indoor situations where you don't need reach and can't afford over penetration.

Put on the upper and mag that the situation needs.

Cuz I'm sure no PD is about to switch to 300BLK. The CMMG gives a smaller logistic footprint.

I too was subjected to the 'orrid L98A1 and its crank handle organ grinder desperation… The kids these days don't know they're born with their semi auto only variants.

I like the fact they use the PMAG footprint just converted to feed 9mm, looks like they have a long shallow feed ramp built into the mags to aid feeding reliability too?

Bloke, this is in no way a criticism, but rather an honest Question.
Why is your red dot there? I am new(ish) to red dots and I find people mount them up and down the rail. The owner of KE (That lower if I'm not mistaken) Mounts his red dots a good 4-5 inches farther from the eye then you have yours.

Is this all just personal preference? Or are there mounting points based on shooting styles that I just don't know about?

Such a cool set up. A suppressed sbr
In this setup would be dope!

The problem lies in the fact that the Stoner system was intended for rifle rounds operating at 50,000 psi+. Altering it to work with pistol rounds means you literally have to cut corners. Just stick with good ole 5.56!!! IMHO.

This thing is incredibly cool.

But I made a mistake: I checked how much these cost in Finland. Yikes!

Any alternative that isn't as dirty for pistol calibers? Is the buffer setup that was shipped usually for a much shorter barrel?

thank you

I have a soft spot for delayed blowback systems, the mechanical cleverness tickles me in the bit that is tickled by mechanical cleverness.
I really like how they've managed to do it just by changing machining operations on otherwise standard parts, it does make the push-to-jam button that much more amusing though.

I am looking for an upper like this for a Long time in switzerland but they are all horribly expensive- where did you get it and how mich was it?

I have wondered how the UK straight pull versions work. I assume they replace the spring behind the bolt head with a solid spacer (or something similar), to prevent it from disengaging until you pull back on the bolt?

Great Googly Moogly I have to run a 308 buffer spring and a 8 Oz buffer on my blow back 9mm AR.

Nice. I would love one of these on my spare KP-15, but they're hard to find! Random admittedly nosey question: do you identify more as a Briton or a citizen of Switzerland? A Switon?