I totally agree Sir. I have watched two animation videos about roller delayed blowback and I just got more confused after watching. In this video as you say, a simple diagram with a very good explanation helped me understand the concept of this roller delayed blowback system almost immediately.

That diagram is beautifully illustrated also. All those beautiful labels are so much finer level of detail than you usually see on Wikipedia or wherever. Looks like a physics textbook.

Same here. That together with the movement distances made it really easy for me to understand the "transmission ratio" and friction going on between the bolt and bolt head via the rollers.

Indeed, perhaps it's because I have an engineering background myself (albeit electronic) but a nice technical diagram really did make it all sink in.

@@David-uk3nv Well said. I don't think I'd ever heard of a step ratio being used to describe this mechanism before.

It's covered pretty well - I can do that!

I agree, it's my favourite action

Agreed!

@@BlokeontheRange that would be awesome definitely subbed!!

@@BUZZKILLJRJR kzfaq.info/get/bejne/eq2Tp7CaqNyoY3U.html

No, the "tension" is only given by the angles in the roller gear. Actually it's not really delaying movement, but gearing down the rearward force. The bolt moves immediately under gas pressure, but only 0.5mm or so, as long as the rollers are in touch with their cavities. When they give in, the bolt carrier is accelerated further. Thanks to the gear, the carrier already moved a longer way than the bolt head. If you had no wedge gear like that, you would need a 11kg bolt carrier to take the force of a 7.62*51 in a non-locking bolt assembly (Uzi: 760g for a 9X19). If the bolt carrier and bolt head would not have a gap in battery, the force could travel directly rearward, and the rollers would be bypassed. With a bolt mass below 11kg, as a G3 rifle has, that would destroy the rifle. Actually the G3 bolt assembly is relatively prone to wear. On some worn-out old rifles the gap is almost closed. This was always one thing Bundeswehr gunsmiths hat to take care of to prevent the older rifles from breaking during training. At least that's what Peter Dannecker, author of the book shown in this video, tells during his lectures. Latest edition of the book above, from 2017, has three times the pages as the edition shown here, btw. Dannecker added many new weapons over the years and I heard he is already writing the next edition, although he retired from service several years ago and could go fishing instead.

Yeah I found Ian's description to be somewhat confusing.

"Can't move" is true of roller _locking,_ pretty much by definition - a delay is something that will give if you put enough pressure on it, a lock is something that won't and requires the input of some other part of the system (such as the user's right arm in bolt-action rifles, which are inherently locked-breech).

Chinn's the machine gun is probably the closest. For a more engineering based approach flinn's firearm design book 1 and 2

@@DanielSmith-ui4gr googled that and didnt find anything?

He translated it as "geared" -> gearing in the video, which should be the correct translation of "übersetzt" in this case. It is a "Übersetzung" like you have in a gearbox.

Actually in the manual of the G 3 ( TDV ) it is also explained as translated and not as delayed ( - übersetzter Massenverschluß ) . Of cause it has to be translated because the gases would have escaped before the empty case has been fully extracted. Otherwise the empty case would have been pushed in again- not enough distance - before the bolt has traveled far enough to extract the empty one and feed a new one ... Must have a look what they have written in the manual of my H& K P9S, should have it somewhere ...

@@heikopanzlaff3789 Were can I find this manual?

Too French, although having watched Ians FAMAS G2 vid I found out that the French adopted the HK 416 rifle, when the Manufacture d'Armes de Saint-Etienne (MAS) factory closed in 2002, no more domestic rifles could be made.

Same

well if this doesn't count as maths or physics I don't know what does.

Mister The Geoff too bad I study economics so firearm mechanics don’t really apply to my field XD

Glad it was helpful!

shame i can't find a english translation of this!

It is roller locked short recoil unlocked not roller delayed. 👍

And then Evan Jones made a gun where it literally gears down.

Dannecker clearly didn't though! :D

He's right though - the case acts as a piston in a blowback system. If any form of gas action is used for operation, whether it be convention gas operation, direct impingement or some form of blowback, there's ALWAYS something acting as a piston and something acting as a cylinder, one of which is moving and the other is stationary. In the case of blowback, the chamber is the cylinder, the case is the piston.

@@BlokeontheRange Of corse i know he is right, i have previously calculated boltface force for locked rifles and kinematic calculous for unlocked delayed systems , just that he calls straight blowback a directly gas operated system It just sounds extraordinarily different to the usually used therms in my enviroment

Most people who write about these things simply haven't thought that deeply about it :)

@@BlokeontheRange I had the idea lately that blowback-operated could actually work for caseless if you just had the bolt face telescope out and follow the round into the chamber (like an advance primer ignition bolt). In the light of that it makes sense to think of blowback as involving a piston. In fact, in this case, you would even want piston rings on it...

R Blake Stevens on page one of Full Circle says so, too.

Nope. If you draw it out and set up the equations just using a simple lever à la FAMAS to make life easier and then reduce the model to an equivalent simple linear one looking at what the point of application "sees", it's simply M(effective) = M(nominal).(lever ratio). And F=m.a so... I'm not seeing where you think there's a square term coming from... You can even look at it in terms of conservation of impulse (force x distance) and you get exactly the same result.

@@BlokeontheRange I think you mean conservation of energy (force x distance) as impulse would be the integral of force over time. If the front of the bolt moves by x distance then the portion which is subject to the mechanical ratio moves by ratio*x. But this also must mean (by conservation of energy) that the force transmitted to the faster-moving portion is F/ratio. So an applied force F on the slower part, translates to a force of F/ratio on the faster part, producing an acceleration of F/(M(nominal) * ratio). If we translate this back to the acceleration of the slower part, we get (1/ratio) * F / (M(nominal) * ratio) or accel=F/(M(nominal) * ratio ^2). If we recast this as F=M(effective) * accel, then M(effective)= ratio ^2 * M(nominal). This is a very well known result for rotary motion where mass moment of inertia is transformed by the gear ratio squared.

Energy is not conserved in such a system, which is why we have the concept of the energy efficiency of a mechanical system. Momentum is. But you don't need to go anywhere near movement, cos you can solve it statically. Seriously. Just draw it out and stop trying to over-complicate it. We're not doing rotary motion here (where squares can indeed creep in). The simple question is, for a mass M at a lever arm L, what is the equivalent mass for a 1-dimensional system? It's simply M.L...

@@BlokeontheRange We're talking about effective mass due to acceleration, right? Not static force due to gravity. The situation here (roller delaying) is inherently dynamic, involving inertia reflected through a mechanical advantage.

@@BlokeontheRange Sure, let's look at the simple lever. Let's say it's set up so that the distance from A to the fulcrum is 1 meter and from the fulcrum to B is 2 meters. If I push A forward by 10cm, B moves by 20cm. If I accelerate A at 1m/s^2, I will accelerate B at 2m/s^2. If I have 1kg at B, the force required to accelerate B at 2m/s^2 will be 2 newtons. But to apply 2 newtons to B requires 4 newtons to be applied at A. So to my hand, point A "feels" like a mass of 4 kg, not 2 kg. Conservation of momentum has no meaning in this system because there is only one real mass, so there's no transfer of momentum from one mass to another.

So I ordered the book. :) If you like to know more about how to make gunbarrels and guns themselves you can contact me. I dont know if there is a chat function on youtube. But ive got tons of books about this subject. Its a collection that i started about 2 years ago. Or if you like 3d cad programs, you can come take a look at my drawings: grabcad.com/a.b-430/models. (sorry but it feels a bit like im pushing my stuff down your throat, but i think you might like it)...

@@jeffjefferson2676 you have peaked my curiosity sir but I must ask does it include polygonal rifling and what edition the particular book you ordered?

@@gnomemcshroom7476 I ordered the book he is reviewing. Its handy to see how it all works. The game "world of guns, gun disassembly" is also a cool game if you want to see how guns exactly work. So if you have both the book and the game, and the blueprints, you get how things really function! :D And i have a large collection of firearms blueprints!! I will scan my single shot rifle blueprints soon, because i bought that, and they are not online yet. So that will come in the near future. Any way, some good books on (button)rifling is: "Gunsmithing and Tool Making Bible By Harold Hoffman", and his other book on making a button rifling machine. Yes you can get polygonal rifling with that, as long as you can cut the button the right way. Now for my full research on all the books, including my findings i got by emailing with the president of Drill Master Eldorado Tool gundrill company. Check out the grabcad page with all the gundrills and buttons. Just make an account and download my projects. Also get a(n) (illegal) copy of Solid Works. And check it out. It is worth the while, i put in a lot of hours/days into the research, and im convinced you can make top of the notch gunbarrels/ammunition with my research and all the included books. Also the chamber reamer stop is something you really want to have when making barrels. Its the best tool out there for manual barrel reaming! Now i did not upload the heattreating kiln yet. Because i stil did not write a good program for it. I did talk to people with knowledge about heating elements and using solid state relays; you want to have the heating element to heat up fast or cool down fast, but once it gets close the the temperature you want to attain, you want to relay to start to go on and off either shorter or longer, depending on the temperature going up or down. You dont want to over or undershoot your temperature goal. Now any way, you can do that with a solid state relay you cant use a normal relay. Using an arduino you can switch things on or off as fast as the frequency of the crystal that is on the board. Thats 16000 times each second. So you can really make a precise instrument with those things combined. They said something about differentiating, so that you get a 0 reading on the differentiation of the temperature curve, so you keep a constant temperature when you reach your temperature goal. Now i dont know about how to write the arduino text for that just yet. But now you know what to look for. It should be doable. Greetings, Jeff

Yes I do

Bloke on the Range Sorry for the slow reply, been extremely busy with work! That’s brilliant though, do you prefer it more than home? I was thinking of visiting (after Covid-19 dies down.) Can unlicensed civilians pay for range time? :)

I have the 4th ed here in my hands. Only color page is the title page. Inside all drawings are exactly like in the video. Just three times as many weapons are covered.

Neither the Bloke, nor really an engineer (studied Physics and worked in Materials Scinence for a couple of years), but I'd not specialize too early (which, in my case, was one of the arguments of choosing physics over engineering). You might come across some really intresting stuff you'd never have considered otherwise (it was solid state physics for me) and you've got more options if you want to stay in Australia (I'm assuming here, but Australia isn't exactly known for its huge aerospace industry) or Aerospace doesn't work out for some reason. I'd try to find a University with a good aerospace programme (possibly also exchange programmes), start with plain mechanical engineering and go from there. It depends a lot on how sure you are what you really want. If you definetly want aerospace, even if it means sitting somewhere in Germany of France, designing tiolet bowls for Airbus for years on end (know a guy who did that), then the answer is different than if you want to be an engineer anf find planes and rockets kinda neat. In the end, I think, it doesn't matter how easy it is to find a good job with your degree if you don't care enough to finish it and it doesn't matter too much what your degree is in if you're passionate enough to actually learn something instead of just passing exams.

I did a general course that was accredited by the IMechE and IEE irrespective of what options I took. I ended up taking a lot of chemical engineering (although didn't get accredited for that cos I did a mechanical 4th year project) cos it was interesting, I was good at it and mostly cos the lecturers were actually good teachers... If you're sure you know what you want to do, go for it. At 18 I was sure I wanted to do electrical engineering, which wasn't the way I went at uni or afterwards and had I ended up at a different uni I'd have been doing electrical engineering, which with hindsight would have been a mistake. If you can find something broad that lets you specialise later, go for that.

@@BlokeontheRange pretty much all the engineering courses here have a general 1st year and then you choose your speciality in the 2nd, so I can at least wait a year before having to choose

I've got MEng (hons) after my name an'all! :D

HerrHornPlayer In theory yes, you don’t need to make the extra parts needed for gas or recoil operation. In practice making a roller delay that works (and is reasonably durable) is hard enough that the guns using that system usually weigh and cost about the same as gas operated firearms.

Brian Smith-Winsemius I was thinking about the roller locking, not roller delayed. To my non engineering eye the roller lock is a evolution of the flapper locking designs. The advantages and disadvantages of roller delayed vs a locked breech vs simple blowback seem a bit more straightforward.

No, which is really why they're out of favour for rotating bolts or BAR-type swinging links, which are far simpler to produce.

@@BlokeontheRange BAR system is favoured? What gun uses it?

I think there would be savings at design time rather than in manufacturing or in use - I can see no need for anti-preëngagement in roller locking.

HK rifles are roller delayed, like the lower picture, not roller locked.

It's not a question of kinetic energy... For every mm moved, the energy required to move it is simply force x distance but we don't even need to go there: it's just a question of forces and Newton's laws, try drawing a force diagram and resolving the forces then doing F=M.a (F being the same in each case and resolving for a).

@@BlokeontheRange Don't forget the linkage is also transmitting force from the bolt into the frame, reducing the impulse transmitted into the carrier.

I'm looking for the same thing, buddy

I would imagine those systems are somewhat susceptible to crud getting around the interface between the barrel and it's casing. As that increases the friction and force required to cycle. So when you get something like mud around it you can get in the situation where you firing the cartridge does not impart enough momentum on the system to move it back with the increased friction. Additionally, if you look at something like the chauchat (long recoil) you can see a large amount of mass jostling back and forth, which is maybe not all that pleasant to feel as you basically have the bolt+barrel slamming backwards and then in 2 parts forwards again.

One problem is the barrel rattling around inside the front bearing. It can never be as accurate as a fixed barrel. But most pistols still use short recoil (Browning) -and long recoil- or no lock at all.

On rifles, because you have to move the entire barrel in a short recoil system. That has some downsides (entry for crud, changes in barrel weight from suppressors etc). Gas operation lets you keep the barrel in place and avoid all that faff. On pistols, it's the reverse - fitting a gas system in place is challenging due to the small size, so short recoil operation is still very common.

And pistols have a fraction of the inherent accuracy of rifles, so aren't anywhere near as sensitive to things like moving barrels - you've got 2 layers of slop there in a Browning-type dropping barrel - barrel to slide (minimised by forcing the rear of the barrel upwards) and slide to frame, which is significant. But aside from custom gunmakers, nobody is attempting to build even a 4 MOA semiauto combat pistol.

@@BlokeontheRange Thanks so much! Enjoy your channel

Yes. But I reject CMMG's term "radial" cos there's nothing acting radially, it's rotary: kzfaq.info/get/bejne/gK1mf5mC19S9inU.html

@@BlokeontheRange Karl Maier would have called it 'semi-rigid rotating bolt'. This is a good term.

Same here 🤣🤣 Did you find it ?

@@ABO3LYY it's on eBay

It allows for a lighter spring than straight blowback, and is an alternative to a typical Browning lockup. But you'll note that the market is dominated by Browning lockup pistols and delayed blowback are rare.

​@@BlokeontheRange That was a quick response, thank you so much! I had a feeling that would be the case, thank you so much for confirming, and yes i have noticed one is more common then the other 😊

I think I explained it that A requires something else to retract the carrier, whether it be gas op or a recoil based system.

@@BlokeontheRangeyeah gas pistol makes sense. Any recoil based situation would have to rely on the weapon moving under recoil given the locking piece. I have an SP5, was curious how the roller delayed actually worked.

Unfortunately not, to my knowledge.

Well dang, that looked like a great book for someone who’s an engineer and firearm enthusiast like my self.

@@BlokeontheRange There are more recent German editions, but none in English so far. I think Mr Dannecker is not going to translate it himself, but he might be open to have a translation made, if someone turns up who is good with languages and understands gun mechanics as well. I could ask him via E-Mail about is opinion, but I fear a few youtube comments would not sufficiently prove the need for an English edition.

Chinn’s The Machine Gun is 5 volumes of gun nerd information. Available online as a .pdf

Pressure from the rollers on the angled surface of the central locking piece .

The case is not sitting against the carrier. It's sitting against the bolt head. In roller-delayed blowback, the bolt head moves. The rollers make the carrier move at a greater velocity than the bolt head. In the case of roller-locked, something else makes the carrier move with respect to the bolthead (either a gas system or a recoil system). Nothing I've written here wasn't said in the video ;)

@@snowflakemelter1172 Now I see it. Thx

Bolt carrier can be wherever you want it in either case. Roller-delayed systems get very dirty cos an awful lot of gas comes back into the action since it's opening at fairly high pressure, and it's that gas that's driving it. Not friendly for suppressors cos they change the residual pressure curve, lengthening it cos they present resistance to gas escape from the muzzle (which is how they suppress), leading to higher residual pressure during the extraction cycle and even more gas coming back into the action.

So it creates gas overpressure. Does prolonged suppressor use on these guns become potentially catastrophic? I’ve had people tell me that the G3 and similiar guns destroy brass and make them practically unreloadable. True or false?

Yes, and roller locked needs some mechanism (gas or recoil) to open the lock. Roller delayed does not.

@@okaro6595 the CZ52 and the P9S have the recoil spring linked with the barrel.

That ("they are the same") is only true if the roller-locked gun were manually-operated. If it were self-loading (and, like-with-like comparison, the delayed one was too, but then blowback-operated is always self-loading), there needs to be an unlocking to the locking, and so there's one more difference between the two, which would be a gas system or whatever is actuating the unlocking.

It's nominally the longest one, but due to tolerancing (and occasional hand-fitting of used ones) there's actually an overlap in the size ranges.

@@BlokeontheRange thank you!

Congratulations, you've just re-invented the "hesitation lock" which is so successful it doesn't usually appear in standard texts nor in many commercial designs ;)

@@BlokeontheRange thanks for clarification. Indeed, it looks like the principle is the same as in R51. I'm still hopeful there's more for us to (re)invent, no matter how successful and plentiful particular commercial designs were before.

Und dreimal so viele Seiten hat.

The latest edition is on amazonDOTde, but still German-only.

No, sorry

@@BlokeontheRange time to brush up on my German then I guess. At least the maths and diagrams are universal

All the variables have the same letters, luckily, so at least the language of mathematics is universal :)

@@BlokeontheRangeTrue. But Bloke is bi-lingual, and thus could be published as a translator...

@@BlokeontheRange and I'd buy it too

Nope, unfortunately...

Chinn’s The Machine Gun is 5 volumes of gun nerd information and is online in .pdf

Neither. They're just different.

You can see that between 0:29 and 0:34 Title : Verschlußsysteme von Feuerwaffen Author : Peter Dannecker Editor : Journal-Verlag Schwend Gmbh

he gave the name at the start of the video

@@Zorglub1966 I asked for ISBN is because there are many different edition bears same name

Unfortunately not, which is a shame...

@@BlokeontheRange sorry to hear that. Thanks for the answer and video.

Not really - they're just different.