Roller-Locked AR

[Nolo]

Why hasn't anyone done it?
It's always been a fight between the DI people and the piston people and I was wondering why didn't anyone just get the best of both worlds by putting in a roller-delayed blowback mechanism?
Is there a good reason for this? It seems like the system is well proven in the G3, HK53 and MP5 weapons.

 

[rcmodel]

If it was roller locked it wouldn't be an AR.

It would just be a CETME or HK-93 in .223 caliber.

IMHO: Delayed blow-back in high power rifles isn't such a great idea anyway.

The CETME & G3 had to have a fluted chamber to allow gas flow to loosen the high pressure stuck case enough for extraction. This blows crap into the chamber just about as bad as an AR, and almost destroys empty brass for reloading due to the flute marks.


rcmodel

 

[jerkface11]

G3's aren't roller locked it's roller delayed blowback. They only work with a fluted chamber.

 

[jerkface11]

Dang RC beat me to it.

 

[Nolo]

I do believe I said roller-delayed blowback.
Militaries don't care much about reloading, and you could just flute the chamber.
You could still use a long recoil spring, just like the AR always has.
Not to mention the AR is a lot lighter than an HK53.

 

[rcmodel]

It wouldn't be lighter, if you had to build it out of steel to handle the stress of a roller delayed locking mechanism in the receiver.


rcmodel

 

[Nolo]

Fair enough, RCmodel.
I want to know what the MAS-49, the Ljungman rifle and other DI guns are doing that the AR (at least the early versions) aren't (weren't) doing.

 

[rcmodel]

Nothing that I know of.

But I am of the opinion that the AR/M-16/M-4 Direct Impingement system gets blamed for a whole lot of things it doesn't cause.

Part of it is from the early days, when M-16's were issued without cleaning equipment and non-chrome bores.
BTDT!

Part of it is due to the military tradition of "White Glove" inspections.
That makes a new GI in Basic Training hate cleaning the "dirty" M-16 right from the get-go!

Part of it is due to issuing the same old worn-out mags until all the finish is gone and the body cracked.
No rifle design will work right with worn-out mags!

Sand is another factor we hear about now, but again, that has nothing to do with the DI design. That has to do with the tight fitting parts.

We make them tight on purpose, so they shoot more accurately then any other combat rifle in the world.
And then we bitch because they get full of sand & quit working if we don't keep them clean!
Give me (and the M-16) a break!

Another factor is the AR-15 has been made by more fly-by-night companies, and kitchen table gun cobblers, then any other firearm.
(Well, maybe the 1911?)

After 45 years of that, there are an awful lot of just plane BAD AR's floating around, that don't work right when dirty, and didn't work right when new & clean!

It has been my experience for close to 45 years now, that a dirty Mil-Spec M-16 or AR will keep running forever as long as you keep it wet with a little oil, and use good magazines & ammo in it.


rcmodel

 

[Nolo]

RCmodel, I always love your input.
I really do hate the magazines on the AR.
The weapon is good, I know.
I was just wondering.

 

[HorseSoldier]

Lots of people trumpet the fact that the AR is basically the only direct gas impingement rifle design out there in the modern world, but if you look the roller lock hasn't been much more popular in rifle designs -- basically limited to CETME/G3 and various HK offshoots from that and I think the Sig 510. In just about all cases where a military has had the money to develop or buy a replacement for a roller lock rifle, it's been a gas piston design.

 

[gunnie]

wouldn't pretend to know the particular reason that whatever military didn't get, doesn't get, or got rid of this action type. i have heard it is a reliable, long lasting design.

I DO KNOW THAT I'D HATE TO BE IN A FIREFIGHT FOXHOLE ON THE DOWNSTREAM SIDE OF THE EJECTION PORT....

medic! MEDIC! another brass casualty!!!

usually the semi/fully wartoys that jam from mung and spoo exposure have tight fitting bolt carriers. on the other hand [see above] this is a characteristic of the most accurate semi/fully designs.

choose wisely, grass hopper....

gunnie

 

[jerkface11]

Ok you said roller delayed in the post. But the title of the thread is roller locked. Why not a tilting bolt AR? look at all the successful tilting bolt rifles out there.

 

[stubbicatt]

Gunnie has a good point there.... being hit with an empty ejected from a G3 fired by the squaddie in the hole next to you might get you the purple heart. Although the port buffer does seem to mitigate the transsonic ejection speed on those rifles, and redirect the empties towards the ground.

The M16 series of rifles is plenty good for most applications. The climate in mesopotamia and Afghaniland is not friendly to anything mechanical. I suspect that *may* have been a consideration of those governments in that area who adopted the Kalashnikov system of rifle for their guys, or perhaps it was simply free rifles from the Soviets.

Perhaps it was experience, perhaps it was expense, but the Iranians under the Shah had the G3, but by the end of the Iran/Iraq war had largely switched to the Kalashnikov. I wonder whether this change was precipitated by some sort of battlefield failures in combat, or some other factor(s).

 

[Evil Monkey]

It's always been a fight between the DI people and the piston people and I was wondering why didn't anyone just get the best of both worlds by putting in a roller-delayed blowback mechanism?

What does roller-delayed systems take that are good from "both worlds"?

Is it accurate like DI? Sure

Is it clean like piston? Hell freaking no. Delayed blowback guns are EVEN MORE dirtier than DI guns.

Delayed blowback is also far more expensive to manufacture than any gas operation mechanism.

Delayed blowback is disappearing, slowly becoming an obsolete mechanism.

 

[Slamfire]

I don’t like the direct impingement gas system of the M16. Of all the hundreds of not thousands of assault weapons designs that have been produced since the 50’s not one other uses this system. I think this shows that the Stoner direct impingement system is an evolutionary dead end. However the US has purchased so many of these weapons, and given out so many more for free, that the M16 gas system will be in service for decades to come. Which also shows, while it may not be best in its class, or perhaps even above average, it has been developed to an acceptable system.

Examining the excellent book “Assault Rifle” by Maxim Popenker and Williams, Heckler and Koch made a .223 roller bolt rifle, the G41. But in subsequent designs, they went to gas piston.

While it seems “obvious” that changing from impingement to roller bolt would be easy, seldom does change for change’s sake improve the reliability of any design. It would take a lot of money, testing, etc, to make it work, and then the problem is, if our Armed Services find an “average” system such as the M16 acceptable, who is going to push for the change to something new and uncertain?

And remember the political angle, considering the Congressional support Colt was able to rally against the XM8 program, what General Wannabee wants to fight that snake pit? http://dodd.senate.gov/index.php?q=node/3270&pr=press/Releases/04/0709_b.htm. Supporting any weapon system other than a Colt produced system sounds like a wonderful way to end a promising military career.

Few procurement decisions are based on technical merit alone.

 

[jerkface11]

Better is the enemy of good enough.

 

[HorseSoldier]

Of all the hundreds of not thousands of assault weapons designs that have been produced since the 50’s not one other uses this system.

I think you added a couple zeroes to your figures for the number of assault weapons that have been developed since the 1950s. Gets even smaller if you collapse the numbers to not count "AK clone A, B, C" as three different weapons, etc.

Supporting any weapon system other than a Colt produced system sounds like a wonderful way to end a promising military career.

Colt has lost more contracts than they've won since the adoption of the M16. So far as I know, the guys who signed off on passing them over for the M9 Beretta, Mk 23 pistol, SAW, etc., all went on to successful careers.

In any case, it appears that killing the end run around the procurement system that HK tried with the XM8 was for the best, even if the motives of Colt and other complainants was their desire to bid on an open contract.

 

[Slamfire]

You must allow for some unintended hyperbole. I had no idea of how many different assault weapons were out there until I got Popenker’s book. Now it seems like millions….

 

[ny32182]

To the original question about a roller locked AR, well, you would have to change the entire receiver material/design, totally different bolt/barrel extension design, totally different carrier design... the answer is that when you were through, nothing about it would resemble an AR. I suppose it would be possible to make a roller locked upper that would fit on an AR lower, but that would be about the only characteristic likening it to an AR.

I also agree that the force of ejection in a roller locked gun (or a mini 14 for that matter) is downright dangerous. I will not sit to the right of a guy at a range that is shooting one. You take a flush shot to the face or neck from a case moving at that velocity, and its gonna hurt. And if it hits your gun instead, you're going to need a re-finish.

 

[gunnie]

"I don’t like the direct impingement gas system of the M16. Of all the hundreds of not thousands of assault weapons designs that have been produced since the 50’s not one other uses this system. I think this shows that the Stoner direct impingement system is an evolutionary dead end."

SlamFire1, i have read that eugene stoner still endorsed this system, but could no longer use it due to colt owning the patents. hence his Cadillac Gage owned "stoner 63" system. same-o perhaps for armalite's subsequent AR-18.

still, even with the delayed-roller, i agree with you that one doesn't need to be a weapons engineer to find faults with the idea of expelling HOT, powder residue laced fouling gasses into the reciever area.

gunnie

 

[Destructo6]

HK G-41...look it up on HKPRO.

 

[KC&97TA]

I agree with rcmodel's post.

The M16 was designed to be a "light automatic rifle"... kind of like the M249 that we use as "light machine gun". The DI of it allows a cyclic rate of 700 rpm, which is impossible to acchive with 30 round mags, drums or B mags. It does a pretty darn good job and is one of the most popular rifles in the world, used and produced by 22 countrys. I've never been a fan of the piston uppers as a combat weapon, they cycle too slow and just feel 'funny' to me personally. What has topped the M16... the AK, which is a piece of crap, sold for $6 in some countrys. I'd like to know why the sights on the AK extend out to 1200m on some of the Russian ones... someone had some wish full thinking... but a M16A4 with a RCO, trained shooter and a good wind spotter, can push past 800m, Got forbid someone has a deer rifle scope brought from home, I've seen guys push 5.56 green tip to 1000m, only haveing trouble with the windage and not elevation.

I've shot tens of thousands of 5.56mm NATO, and litterally insturcted watching Millions of rounds go down range. Maybe it's that I instruct to a different caliber of men, maybe it's been luck or maybe all the bugs have been worked out of the M16 variants... the most common problem I've seen is hammer pins working thier way out of the recievers on M4's, thats the only thing I've ever had to employ the Armorers with on a M4 in the last 9 months. Corbon and CLP combine to make a decent grease to keep everything lubed in my opinion.

A good Marine or Soldier cleans his Rifle and Guns every day, or at least checks it... or may have to clean it several times a day, it's called disipline and once your life relys on it, you'll understand, a little carbon on the bolt is a pleasure to clean

 

[gunnie]

just one problem with that premise, the gas piston operated AR-18 has a higher cyclic rate than the direct gas impingement operated M-16. i'd gues this to be due to the 18's bolt carrier riding on twin recoils springs causing less drag, rather than on the reciever as with the M-16.

don't recall the company name, but there used to be an "anti drift" stainless steel pin that was retained by "E" clips on both ends for AR-16/18 style rifles. WORK GOOD. get the armorers on this trail of pursuit. you'll be gald you did.

gunnie

 

[KC&97TA]

don't recall the company name, but there used to be an "anti drift" stainless steel pin that was retained by "E" clips on both ends for AR-16/18 style rifles. WORK GOOD. get the armorers on this trail of pursuit. you'll be gald you did.

They're called "anti-walk" pins http://www.impactguns.com/store/LR-AW.html they're also an "illegal weapons modification", ... the first step is to replace the pin, if that doesn't work there's a little bit bigger pin to replace it with... if that doesn't work, you reissue another M16 and send the weapon to be remanufactured if it's new enough it is sent back to Colt or FN for replacement.

 

[gunnie]

KC&97TA,

"illegal weapons modification", do you mean for military issue weapons? if so, this ruling should be at least reviewed, or better still, the "anti-walk" pin system should be adopted, across the board. in the kind of quantity the military would require, i'd guess these could be obtained for less than one dollar per unit.

i just looked at same, and:

1-my above posting is WRONG, they have a shoulder on one end, and an "E" clip on the other.

2-the same 5.56 bullet point that will push out the OEM pin will remove the clip.

if you mean for all forms of weapon modification-[sillyvillian included]-please enlighten itself, i sure as @*%$ don't need any ATF problems. isn't there any kind of "grandfather" clause, as i bought these way back in the late '70's, with NO kind of paperwork required at all.

gunnie