Is a roller delayed blowback AR possible?

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>Krazy

Back to the original point of this post, I agree that a piston operated roller locked rifle would be an interesting concept that might be worth pursuing.

In my original post I did not propose a piston operated roller locked design, I just mistakenly called roller delayed blowback a roller locked action.

However I believe I clarified that in the following posts.

Post #28
All I am asking is that this great design be brought into the 21st century with a modern two piece upper-lower design like the XCR did for the long stroke gas piston Kalashnikov style action.
The specs would be as follows:
1 H&K style roller delayed blowback action.
2 the lower must contain the magwell, the trigger group, grip, and buttstock.
3 the upper must be a milled alloy flattop.
4 the barrel must be easily free-floated.
5 if it is chambered in 5.56x45 it MUST accept stanag magazines.
6 if it is chambered in 7.62x51 it should use a common, readily available, non proprietary magazine.
7 a last round bolt hold open would be nice but not necessary.
8 it must use a drop in trigger group.
9 the charging handle must be non reciprocating and on the side of the rifle.
10 a built in port buffer would be a good idea.
11 it must be easily field stripped by hand.

That pretty much sums up the requirements for a modern roller delayed blowback rifle.

Sadly it would probably sell for $3,000 or more

Post #36
Thank you Krazy, the meritless hostility towards the roller-blowback system appears to be the only hurdle in creating such a weapon, that i think would hold its own against modern DI, long, and short gas operated "rotabolts"
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Post #43
I like the roller delayed blowback for its simplicity of operation and secondly it does not impart any asymmetrical or rotational force on the receiver, which helps accuracy.
As I've stated before, I just want to see this legendary action given a proper home in a modern battle rifle receiver.

I own a CETME, the recoil is strong but not sharp, which makes it very controllable, it actually feels softer than my Krebs KTR-08s Saiga AK.
If one cannot handle the recoil on a CETME, one is holding the rifle wrong, especially that guy who said it bruised him.
Also the title of this thread is "Is a roller delayed blowback AR possible?"
I hope that clears things up
 
The proof is in all the crappy HK clones out there versus the originals that work like clockwork. On the other hand it is you you have offered no proof whosoever that the design is inefficient and obsolete.

Citing a couple of threads on an HK forum is not proof that the clones are inferior. I can dig up a hundred complaint/problem threads on any given weapon in the world-the plural of anecdote is not data. This is fundamental logic here.

As for the design, the fact that it requires chamber fluting to work is the first issue. The fact that it tends to have increased recoil, tears up brass upon ejection, and generally has been abandoned by every single modern firearm designer in the world should be known as a "clue". Your only assertion to the contrary is the completely unsubstantiated claim that HK is the only company in the world capable of successfully building them. This is what psychologists call an irrational belief.

I don't claim to be a spectacular shooter but I can dump a 20 round mag in a G3 in FA while holding it on target. It took some practice but it's not difficult. Where is the proof that no one uses 7.62 in full auto. If a truck full of explosives was bearing down on a soldier with a 7.62 rifle, he wouldn't use semi.

You've pretty much just conceded that whole point on your own to anyone who's served in the Army or Marines.

Talk about unsubstantiated opinion. You just took the prize.

Okay, let's take the 416. HK is the only company in the world, to the best of my knowledge, who felt it was absolutely necessary to re-design the entire AR bolt group to incorporate a firing pin safety. Four decades of development, manufacturing, and deployment of ARs on the part of dozens of companies and countries around the world, and suddenly it's necessary to redesign the entire heart of the weapon to solve a non-existent problem. And that's not even getting into their downright insane decision to redesign the mag well, so as to prevent anyone from inserting polymer magazines (Of course, strangely enough HK has an overbuilt and overpriced steel magazine of their own design that does fit the 416...). When you go screwing around with a design and wind up adding parts, cost, and weight, for essentially no gain whatsoever, there's a Problem. One can argue as to whether the gas piston AR has merit or not, but at least there's a semi-legitimate reason there for it. The same can't be said for various other aspects of the rifle.

Most countries that adopted the AK-47 did not do it by free choice so your point is moot. Nothing wrong with a good AK though.

There are plenty of countries that voluntarily adopted the AK on its own virtue. India, Finland, Israel, South Africa..any of those ring a bell?

Again, you are showing more of your unfounded bias. What's wrong with ARs?

There is no unfounded bias (nice try though), I just like shooting a variety of weapons, and ARs are ordinary.

If you really think that then you are seriously disconnected from reality. Macs have always been one step above junk and the price they fetch is proof of that.

You've quite obviously never shot a Lage MAX-10. I'll take one over an MP5 any day of the week.

I like the roller delayed blowback for its simplicity of operation and secondly it does not impart any asymmetrical or rotational force on the receiver, which helps accuracy.
As I've stated before, I just want to see this legendary action given a proper home in a modern battle rifle receiver.

Just what loss in accuracy is caused by a rotating bolt? Can anyone please quantify it?

I own a CETME, the recoil is strong but not sharp, which makes it very controllable, it actually feels softer than my Krebs KTR-08s Saiga AK.
If one cannot handle the recoil on a CETME, one is holding the rifle wrong, especially that guy who said it bruised him.

I know people who think that .375 H&H Magnum is a light and comfy caliber. I agree that you're probably doing something wrong if you're being seriously bruised by a .308.

Let me repeat..

AS far as the reliability of the MP5.. Per Frank James MP5 book "project 64"


NASA owned a MP5 that shot over 571,000 rounds before being decommisioned. The MP5 SN 316019 went in service August of 1984 and come out October of 1992.

And what was the number of Mean Rounds Between Failure? The information you provide simply says that NASA fired half a million rounds through the weapon...it provides zero information as to how well the firearm performed throughout that period.

There have been a few design blunders over the years, the Chauchat and original SA80 come to mind, but almost all of the battle rifles that have been fielded in quantity are decent weapons deserving of respect in their own right.

The M1 Garand, MAS 49/56, FN-49, SKS, and Ljungman are all rifles that did quite well in their time, but are simply obsolete in the world today. Yes, they work well. Yes, they all have long and illustrious histories (mostly). But that doesn't mean that they're better than a modern rifle that has the benefit of half a century of design improvements.

As Cap'n Jack Burntbeard pointed out, one of the real advantages of roller lock design is it's lack of asymmetrical or rotational force on the receiver.

You could make a symmetrical piston but it would have high reciprocating weight unless you could made it mostly from carbon fiber or some other high tech material.

So, you would loose the symmetrical advantage by using a piston, but still have no rotational force. Of course the SKS, FAL and VZ58 also have no rotational force so you might just be re-inventing the wheel. Both Stoner with the AR and HK with the G36 did keep rotational mass to a minimum because the lack of twisting motion does improve follow up shot and full auto controllability.

The M14 and to a lesser extent the AK are rifles that have a little to much rotating mass for their own good.

The question is, with the small rotational mass in a AR, would there be a noticeable advantage by getting rid of it.

What is it with this fascination on non-rotating bolts? The AR platform uses a rotating bolt, and it's widely considered one of (if not the) most potentially-accurate common selfloading rifle platforms around today. Realistically, there's strong evidence that it's just not physically possible to improve the accuracy of an autoloader beyond that of what a good AR can already do. Accuracy problems with the M14 can be traced largely back to bedding issues with the stock.

I've yet to see any evidence that a roller locking rifle has any intrinsic accuracy potential over that of an AR, or a well-made gas piston design.

So much misinformation. This is why people on other boards think The High Road is a joke of a forum.

Indeed.
 
Wes, I think we're beating a dead horse here. I think we've said enough so that future readers of this thread can examine the features for themselves before deciding which expensive gun to put their money on.

I do want to respond to one thing:

I know people who think that .375 H&H Magnum is a light and comfy caliber. I agree that you're probably doing something wrong if you're being seriously bruised by a .308.

Yes, I got bruised from firing my PTR-91 - only one time, but that one time was unpleasant enough. Heavy recoil and awful stock design, especially in relation to the sights. For comparison, I do not get bruised when I fire full-power 12ga slugs out of a 6 1/2lb shotgun, up to a few dozen in a practice session, and as I mentioned I find my M1A a pussycat. I could probably fire my M1A 300-500 times in an afternoon without it wearing on me.

Anyway, everyone enjoy what you like, and comparison shoppers, do your research!
 
OK hear we go again,
E.M. I will give you the first of your quotes from my posts,
Inhierently improved accuracy due to lack of torque in the action
I didn't specify that I was talking about full auto fire, and in my experience HK's are more controlable than other FA battle rifles I have fired, mabey there is another reason for this but that has been "MY" experience.

No gas system to break or foul
Now I guess that you are going to tell us that the all of these weapons do have a gas system, ie gas port, gas tube, gas piston, or gas block, please tell me where it is so I can clean it.
Comparibly fewer moving parts to wear or break
Other than the DI-AR operating system, the roller locked HK "HAS" fewer moving action parts than "most" other modern battle rifles that use gas piston actuation to cycle the action, but then again according to you HK's may have a gas system somewhere.
Lighter recoil in all calibers compared to other designs.
Once again we come to "MY" exrerience, I have several weapons chambered in 7.62 and several chambered in 5.56, and I find my HK's much milder in the recoil department and more controlable in rapid fire exercises, or.... mabey I just dreamed that.

All I have to offer this forum is my experience and opinon, which I think is the whole point, as I have stated before I have no reason or benifit for telling lies to a bunch of faceless nick names on the internet because your acceptance means nothing to me.

Misinformation probably has little to do with some peoples issues with this forum, it is more likely some of the members who are "always" right, have done it all, do it better, did it first, and know more than everyone else does. Not to mention, combative, rude, insulting, and sometimes down right hateful, I know that I would hate to be the butt of others jokes and, if that sort of thing bothered me I would take my ball and go somwhere else.:)


This is this! It's not something else, it's this!

Don't pull it if you don't plan to use it, and don't use it if you don't plan to kill!

ALWAYS REMEMBER OUR MEN AND WOMEN OVER THERE.
 
>Wes
What is it with this fascination on non-rotating bolts? The AR platform uses a rotating bolt, and it's widely considered one of (if not the) most potentially-accurate common selfloading rifle platforms around today. Realistically, there's strong evidence that it's just not physically possible to improve the accuracy of an autoloader beyond that of what a good AR can already do. Accuracy problems with the M14 can be traced largely back to bedding issues with the stock.

I've yet to see any evidence that a roller locking rifle has any intrinsic accuracy potential over that of an AR, or a well-made gas piston design.
The firearm in general , but the auto-loading firearm in particular, is founded on newton's third law, which states that for every action there is an equal and opposite reaction. With that in mind it should be easy to see that rotational, asymmetric, and or laterally uneven forces have a detrimental effect on accuracy, which is why a manual locking action is the most accurate, since all energy is distributed into your shoulder and the breech remains static throughout the distribution of that energy.

In a gas operated rotary bolt design, during the time that it takes the bullet to pass the gas port, energy is distributed into your shoulder by the locked breech, after the bullet passes the port, the carrier begins to unlock the breech and subsequently absorbs a portion of the remaining energy left over from firing, the rest of it leaves through the muzzle, and we all know what the equal and opposite reaction of that is.

In a roller delayed blowback design, the carrier begins moving rearward as soon as the cartridge fires, but does not unlock until the bullet has traveled far enough down the barrel to reduce gas pressure to a safe level, this type of action starts distributing all recoil energy rearward upon ignition, which creates a softer but just as heavy recoil.
The lack of extraneous motion in this design should be self evident by these pictures.
roller1.jpg
roller2.jpg
roller3.jpg
 
The firearm in general , but the auto-loading firearm in particular, is founded on newton's third law, which states that for every action there is an equal and opposite reaction. With that in mind it should be easy to see that rotational, asymmetric, and or laterally uneven forces have a detrimental effect on accuracy, which is why a manual locking action is the most accurate, since all energy is distributed into your shoulder and the breech remains static throughout the distribution of that energy.

In a gas operated rotary bolt design, during the time that it takes the bullet to pass the gas port, energy is distributed into your shoulder by the locked breech, after the bullet passes the port, the carrier begins to unlock the breech and subsequently absorbs a portion of the remaining energy left over from firing, the rest of it leaves through the muzzle, and we all know what the equal and opposite reaction of that is.

In a roller delayed blowback design, the carrier begins moving rearward as soon as the cartridge fires, but does not unlock until the bullet has traveled far enough down the barrel to reduce gas pressure to a safe level, this type of action starts distributing all recoil energy rearward upon ignition, which creates a softer but just as heavy recoil.
The lack of extraneous motion in this design should be self evident by these pictures.

All of which is well and fine, but theory is always trumped by experimental evidence, and the last few decades worth of firearms design and production have clearly shown that rotating bolts don't seem to have any appreciable difference in accuracy compared to other locking systems. Tilting bolts seem to perhaps be slightly worse (at least in the platforms they're typically found in), and there's no particular evidence to suggest that roller delayed actions have any statistical advantage.

The primary determining factors in accuracy are the same now as they've always been: shooter skill, sighting mechanism/quality, trigger quality, ammunition quality, condition of the barrel, and rigidity of the platform. In basically that order. Before you should even begin to care about the last few, the first items need to be near-perfect.
 
which is why a manual locking action is the most accurate, since all energy is distributed into your shoulder and the breech remains static throughout the distribution of that energy.

You do realize that in rifles using gas operation the bolt carrier doesn't start moving until after the bullet is clear of the muzzle? BSW
 
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